LAPD searched the hotel room where Nick Reiner checked in around the time his parents were murdered, and TMZ has been told the police did not have a search warrant.

Harvey explains during the latest episode of the “2 Angry Men” podcast what happened at around 1 AM Monday … when an LAPD detective showed up at the Pierside Santa Monica hotel.

Sources with direct knowledge tell TMZ … the detective told the front desk clerk he was looking for a guest named Nick Reiner. The detective told the clerk he was there for a “welfare check.” But he also told the clerk he was concerned Reiner “disposed of a weapon and used the room to clean and dispose of evidence in a violent crime.”

Our sources say the detective never presented a search warrant to the clerk, and another source connected to the case tells TMZ … there is no evidence police obtained a warrant.

Now here’s the rub. If this were just a welfare check, a warrant would ordinarily not be necessary. But if the real motivation was to look for evidence connected to a crime, then a warrant would be required. We’re told this is already on the radar of Nick’s team. If any evidence was recovered in the room that morning, the defense would almost certainly argue it would be inadmissible.