Can police forcibly extract evidence by sticking a finger down the throat of the suspect before they handcuff him and use the evidence in trial?
After observing a street corner, two officers notice a drug deal and before they can handcuff the defendant he swallows what looked like to be a ballon of heroin, police officer sticks his finger down the throat and makes him vomit revealing a balloon of heroin.
Generally speaking, the police do have the right to do this under certain circumstances. The situation that you have described is not clear or detailed enough to know for sure whether the intrusive "search" conducted by the police officer would be legal.
According to Schmerber v. California and subsequent cases, the police need to have probable cause to do something this invasive. In other words, they cannot simply think that the suspect might have swallowed heroin. They have to have probable cause, not just something like a reasonable suspicion. There must also be "exigent circumstances" that make it so that immediate action is necessary. Finally, the method used to extract the evidence must be reasonable.
All of this means that it is hard to know whether the police acted properly in this situation. The criteria that must be met are rather vague so it is not generally possible to know for sure when an action like this will be found acceptable.
The action of police is not really to retrieve evidence, but for the safety of the person, as if ingested, it could kill.
As Constitutional law permits a warrantless entry into a home to protect, such is permissable as in your example.
Yes, what you describe IS a search, so we need to conclude if it is reasonable, as the 4th AM only forbids UNreasonable searches.
If it was soley for evidence gathering, there could arise a constitutional issue, but as I stated, as any officer would probably confirm, I would guess, it is to protect, not incriminate.
I have this case in my notes, in a way similar, where the SC ruled a search to extract a bullet was UNreasonable. As you read though, it was soley for evidence gathering, not a safety/health act.