The Chicago Tribune reports that a suspect has been arrested for the stabbing deaths of three victims in the past month on the city’s west side. Police released a surveillance video of the suspect in the murders of a woman and two men in their 50s and 60s.

The suspect is a 24-year-old man, but no charges have been filed as of Monday.

All victims were stabbed multiple times near Roosevelt Road. Police don’t know whether the victims knew the suspect or why they were targeted. The suspect did live in Chicago in 2012-2013, and only recently returned a few months ago.

On November 20, Ronald Rockett, 58, was found stabbed to death in a building near his home. On November 15, Refugio Ceja, 64, was discovered with stab wounds to his neck on the ground by someone looking out a window, and there was a blood trail leading about half a block away from the body. On November 13, Ruby Humphrey, 57, was also found on the ground by two people with multiple stab wounds to the neck and head.

The suspect has not been publicly named yet, but police say he doesn’t have a criminal record to speak of in Chicago.