Police say the notes were typed and signed "David Ben Keyes." Police found a person by that name on Facebook, but believe his real name is Courtney Anthony Robinson. Robinson may have recently moved from Santa Barbara to L.A. and may be homeless himself.
LAPD Cmdr. Andrew Smith said all three victims survived the attacks. One victim remains hospitalized.
The first incident was on July 3 near 3rd and Main streets. A middle-aged homeless man was stabbed while he was sleeping. In that case, the suspect was seen fleeing from the area.
The second incident happened in Santa Monica on Tuesday. A homeless man was stabbed while sleeping on a park bench.
Then on Thursday morning, a homeless woman was stabbed as she slept near La Brea and De Longpre avenues. A note was left in each incident.
Police warned homeless people in L.A. to be careful and get checked into a shelter if possible.
Anyone with information on the suspect is asked to call the police.