He told a different story when first interviewed by the police.
On what day was he interviewed? And what did he say?
It has been said he was paid by the paper.
Paid by a local paper for testifying the false in a murder trial?
Do you feel confortable as you imagine all these random people willing to pay money to commit crimes for no gain, and so many people willing risk, to take part in criminal conspiracies for no reason, just for the sake of it?
This is his third tour as a witness in a murder trial. He is an acknowledged heroin user and dealer.
Ok, but many witnsses are.
Even if he thinks he is telling the truth there is no way of knowing because of the time and the drug use.
No, just a moment. For "drug use", we are not talking of a person high on drugs, and not "drugs" in general; this is a person addicted to a drug (not high on a drug), not to any drug but to heroin.
Heroin use is not something healthy in terms of quality of life and is a dangerous substance (due to dosage and power on central systems of breath control), it but does not cause people to be unable to remember correctly and to be a witness. Opioids can have effects on consiousness for a while if the dose is heavvy, but do not have hallucinogenic effects nor effects on memory (while instead alcohol has) and cannot produce any false memories.
Moreover, you cannot dismiss the simple datum that Curatolo appears sure and not confused, he never changes his acount and appears to not have an interest nor a moral inclination for inventing a false story. These are points that you have to consider as you actually hear the voice of a person giving his testimony and answering questions. You cannot just cling to the prejudice that all heroin users are all unreliable: if this were valid as a universal rule, the testimony of a prostitute (or anyone else) who claims to be victim of a rape or robbery should be always dismissed on the ground that possibly the person had a drug use. Which is obviously an absurd position, testimonies of people cannot be dismissed entirely in all cases just because they use drugs.