They aren't sure what his name is and they don't know where he went.
But Fontana police have a photograph of the 40-year-old man who was "secured" in an interview room Monday but still managed to escape and stroll out of the police station.
Detectives say the man who calls himself Ramon Torres and Ramon Martinez Ramirez "goes by many aliases."
Police were investigating a verbal altercation that occurred Sunday when the suspect pulled a gun and threatened to kill people inside a house as he attempted to collect rent for a third party.
Investigators took the suspect into custody Monday morning in the 16100 block of Merrill Avenue and took him to the police station for questioning.
Although the suspect's weapon was recovered, he is considered dangerous, police said.