PEORIA, Ill -- Peoria police have now made a sixth arrest in the Starr Street homicide investigation.
"Why they did it? I can't answer that question. Why would anybody kill another human being?," said Peoria Police Captain Mike Scally when asked a motive for Peoria's most recent murder.
Peoria Police continue to investigate the September 26th double shooting that occurred at 2214 WEST Starr Street.
Three teen suspects, Marquis Flora, Dionte Wells and Charles Smith, are each charged with first degree murder and armed robbery.
Authorities believe 15-year-old Smith fired the bullets that killed 54 year-old Michael Robinson and injured Perry Mollohan.
"I think we've seen in recent years an increase in violence among young people, and that's a fact," said Peoria County State's Attorney Jerry Brady.
Thursday morning a 15-year-old boy was arrested. He and a 16 year old are charged with harassment of a witness and unlawful possession of a firearm.
One other teen, 18-year-old Sharome Krus faces one felony count of obstructing justice.
"They were teenagers and I think that contributes to it a lot is there mentality as far as what they're doing," said Capt. Scally, "And gang activity I think participates in it, is because they're a member of a gang and they're trying to look out for other members of the gang and they're trying to stop other people from taking action against other members of the gang, and that's not going to be tolerated."
Captain Scally believes all six of those arrested are involved in a south end gang called 'bomb squad'.
Scally and Brady said part of the gang mentality is to protect the other members.
"These are potential witnesses to a murder investigation and we will take every precaution to make certain their safety is protected," said Brady.
Peoria Mayor Jim Ardis said the age of these criminals make the 'Don't Shoot' campaign all the more important.
"It's very concerning that we have 15 and 16 year old kids out there committing crimes like that, but as far as I'm concerned that just adds extra emphasis that we need to do 'Don't Shoot' in our community," he said.
Captain Scally says to expect arrests coming soon as part of the on-going 'Don't Shoot' program.