Los Angeles city officials say a search is underway for what they believe is a serial killer targeting homeless people. 

Los Angeles Police Chief Michel Moore said Friday afternoon that one person is believed to be responsible for the killings of three homeless people in separate shootings carried out this week in different parts of the city. 

The shootings occurred in the early morning hours of Sunday, Monday and Wednesday, Nov. 26-29.   

All three victims were killed as they slept alone in open areas.   

Officials are urging people living on the streets to seek shelter immediately.

"Our message to the unhoused community is clear -- do not sleep alone tonight. Seek shelter, seek services, stay together, seek support and we need your help to get the word out," Mayor Karen Bass said.

If you have any information in any of these cases, you are urged to contact LAPD's Robbery-Homicide Division, Homicide Special Section, at (213) 486-6890.