I was just thinking about the Suitable For Framing situation. Dale gave Columbo a key to his place, and thus permission to be there, but iirc by the time Columbo asked to see the painting in the bag, Dale had asked him to leave. So he'd rescinded permission to be in his apartment, which could mean Columbo's prints on the painting would be inadmissible/fruit of the poisonous tree, since Columbo was no longer legally in the apartment.
BUT, Dale let Columbo touch the painting…which would mean Columbo handled them lawfully. So
not
fruit of the poisonous tree. But Dale's lawyer could argue that since Dale had already asked him to leave, Columbo shouldn't even have been there to ask, and could even say Dale felt coerced.
I (NAL) would assume that's a question for the judge to decide, but it's interesting to think about (at least for me). There are a few issues like that which come up in some episodes; iirc in Lady in Waiting (might have been the one with the fake kidnapping and orchids), the suspect asked for a lawyer but Columbo continued to question her, or the bullet-in-the-bedroom issue you mentioned, or at least a couple of episodes where entrapment could be argued.
I'd say about 1/3 of the episodes I find myself thinking, "Any reasonably clever lawyer would be able to get that guy acquitted," but it's still always fun to watch Columbo figure it out!

Me too. Remember, Columbo is most often invited to come around in the perp's attempts to be "helpful" to the case. By the time the perps get testy, it's too late, Columbo has it figured out.

I think for the most part, yes.
I recall a particularly interesting situation in
Suitable For Framing
in which the good lieutenant put his hands on a couple of stolen glass-framed paintings that were in a bag being carried by the murderer, but did not remove them or see them. He was able to prove that the murderer ("Dale Kingston") had the paintings in his bag at the crucial time by showing that Columbo's fingerprints were on them. If Columbo had removed the paintings from Kingston's bag, that would have been considered a search or seizure (done without permission or a warrant), and any evidence pertaining thereto would have been inadmissible. But the mere existence of Columbo's fingerprints on the paintings would
not
be considered a search or seizure, and thus that fact
would
be admissible in court. I thought that was quite clever. (Along with Columbo's sagacious decision to put gloves on his hands later when confronting Kingston with that fact, in order to quash Kingston's predictable response that Columbo had just touched the paintings at that time.)
Contrast that, however, with
Candidate For Crime
, where, if I recall correctly, Lt. Columbo dug a bullet out of a wall in the bedroom of Nelson Hayward's hotel suite, hours before Hayward claimed that he had been shot at. That bedroom was a personal area, and was not accessible or at least, was not supposed to be accessible to anyone but Hayward himself and his invited guests. Thus, Hayward would have had a reasonable expectation of privacy, and Columbo's entering that room and removing a bullet from the wall (without permission or a search warrant) would have been unconstitutional and the resulting evidence would be inadmissible.
But that was a rare misstep, and I think most of Columbo's investigatory techniques would have been considered legally valid.

the murderers admit to the crime so these cases are never taken into the court of law the criminal is taken straight to jail.
I know this is old, but…you do know that's not how that works, right? Like, not remotely. A confession doesn't mean you just go directly to jail for whatever amount of time without any involvement with the Court. The 6th Amendment to the U.S. Constitution guarantees the accused the right to a fair and public trial with an impartial jury of one's peers, the right to confront witnesses and examine evidence, and the right to an attorney, whether one has confessed or not.
Every single one of these cases will have, at the very least, bail hearings and thus potentially bail being granted, discovery (wherein the defendant's attorney examines all of the evidence; the defendant's attorney will of course meet with the defendant a number of times, also), meetings between the prosecutor and the defendant's attorney wherein a plea bargain is made if desired (e.g. the defendant pleads guilty to Second Degree Murder or Manslaughter in exchange for a lighter sentence, or maybe they plead to First Degree and in exchange the other charges–obstruction, evidence tampering, blackmail, theft, whatever–are dropped, or even they plead just to avoid going to trial or avoid the death penalty), which is then taken to a court of law before a judge. The judge reads the charges and the plea bargain into the record, makes sure the defendant agrees to it, and then either approves it (thus officially adjudicating the defendant "Guilty") or–very rarely–does not approve it for some reason, in which case there likely will be a trial.
Or the defendant decides to recant his or her confession, and/or their attorney advises them that the evidence is extremely slim, so they decide to plead Not Guilty and go to trial.
Either way, a confession does not negate or render invalid the accused's Constitutional rights.

Yeah, in a lot of
Columbo
episodes, the evidence is pretty weak (seems damning at first, but on further reflection, isn't so much), and I think that if the murderer would just keep his mouth shut, he'd be able to beat the charges.
Still fun to watch, though.

Probably not but by the end of all of the episodes all of the murderers admit to the crime so these cases are never taken into the court of law the criminal is taken straight to jail.

Thank you. I feel the same way. I come here to get away from all the political stuff.

Can you keep your stupid politics away from here?

It was a long time ago, and it'a a fictional reflexion of police work, as seen on TV.
At least his intentions and his instinct were always on point and Columbo strived for REAL justice. Supported by evidence (as best as was available in those years, filtered through the Hollywood lens.)
Today, will it matter?! USA just elected a liar-in-chief. Justice? Irrelevant. Who cares about facts, or evidence?!

No way. First no cop is ever going to keep showing at your home, your job, wherever he wants multiple times asking all these seemingly weird questions. Doesn't happen that way except on tv with Columbo. Any smart is going lawyer up immediately, any question talk to my attorney. If cop start showing up all over the place bothering you that's harassment, your attorney can solve that, you do not have to speak to the cops without attorney and guaranteed half Columbo's questions would get shot down. The cops in this show are bumbling idiots that mishandle crime scenes, destroy, evidence, mishandle it, etc. I've seen Columbo enter residences with no warrant and be snooping when suspect shows up. Even a public defender could get you off if Columbo did the investigation. If by chance some bonehead DA even tried to prosecute on this bogus evidence any attorney worth be filing a motion to suppress immediately and win. Columbo wouldn't be a cop very long. That said I love the show but it's tv not reality.
I agree with a lot of what you say, esp when used in today's context. I wasn't alive when Columbo was on and always just thought, "well I guess cops and the court system was different back then". I agree today Columbo would have a hard time, but I wonder if back then it was more acceptable to go follow someone around and ask them the questions, and even bring his dog lol. I am guessing it still was tv back then but maybe it would have been easier than today for him.

No way. First no cop is ever going to keep showing at your home, your job, wherever he wants multiple times asking all these seemingly weird questions. Doesn't happen that way except on tv with Columbo. Any smart is going lawyer up immediately, any question talk to my attorney. If cop start showing up all over the place bothering you that's harassment, your attorney can solve that, you do not have to speak to the cops without attorney and guaranteed half Columbo's questions would get shot down. The cops in this show are bumbling idiots that mishandle crime scenes, destroy, evidence, mishandle it, etc. I've seen Columbo enter residences with no warrant and be snooping when suspect shows up. Even a public defender could get you off if Columbo did the investigation. If by chance some bonehead DA even tried to prosecute on this bogus evidence any attorney worth be filing a motion to suppress immediately and win. Columbo wouldn't be a cop very long. That said I love the show but it's tv not reality.

Yeah, that was by far the worst ending to a Colombo episode. In fact, it wasn't even a confession merely a shocked or dismayed facial expression. No way would that be enough to convict beyond a reasonable doubt.

In "Dagger of the Mind" the killers confess only after Columbo plants evidence. This is one of the episodes where I was somewhat disappointed by the reveal and by Columbo's character in general.
I'm also not a fan of episodes in murder mysteries where they plant the detective at the location and coincidentally a murder occurs, for example, while they're a guest somewhere or on vacation.

Yeah,
Any Old Port
is a good example. As far as I can recall, there really was no evidence that Carsini had murdered anyone. Yeah, Columbo caught him disposing of bottles of overheated wine at the beach. Okay, so maybe that proves that his wine cellar got too hot over that warm weekend. So what? What does that prove? That the air conditioning unit failed? Okay, sure. But how does that prove murder?

And the fact that they are so exhausted from his routine of showing up literally everywhere they go and the "Just ONE more thing sir/ma'am!"
Fear not for the future; weep not for the past Percy Bysshe Shelley

The brilliance of Columbo's final reveal is that it's so overwhelming to the killer that he or she ultimately resigns to their fate of getting busted that they don't think of any possible means of escaping justice.

All the eating and drinking on the job would definitely be frowned upon.
"I have nipples, Greg. Could you milk me?"

And sometimes his evidence is so weak, that it doesn't make sense for the murderer to confess.
For example, Murder by the Book, Any Old Port in a Storm, Mind over Mayheim, a Matter of Honor, Old Fashion Murder, to name a few

His methods usually get people to confess so I don't think it really matters unless he was threatening them or planting evidence, which I don't recall him doing.

Should we email you with our thoughts?

There's no reason why that would be inadmissible. You could attack Lt. Columbo's credibility, saying he planted the suture on himself and tried to frame the doctor, but that's different from saying that the evidence is inadmissible.

I am reminded of A Stitch in Crime, where Leonard Nimoy's character manages to plant the incriminating dissolving suture in Columbo's pocket. Columbo doesn't notice it, but thinks to check anyway because it was the only place they didn't search. So Columbo finds the "smoking gun" in his own pocket, and this is supposed to be the "gotcha" moment. But as far as I can tell, it would be inadmissible - Columbo fished it out of his own pocket himself, with his bare hands, and he cannot prove that Nimoy's character put it there. The intended victim is now stitched up in permanent suture, and the villainous surgeon could argue that he reused the suture - but why he didn't bring a spare of permanent suture with him to present to the police (because they were looking for the old suture), I don't know.

I'm not a cop or anything, but I've read he would have had problems with his keeping evidence in his pockets like he did. He did bluff a lot, but that's actually legally OK and done in real life. I get the idea that other people think the bad guys could walk free if they had good lawyers, if he didn't break their spirit, if that's the right phrase.
"I used to be a detective like you, but then I took a bullet to the knee."-Law & Order: Dragon Squad