A Blue Island man charged Wednesday with murdering three young women was suspected in one of the slayings since 2009 but wasn’t arrested until a girl he allegedly raped last summer went to police.

Sonny Pierce, 27, strangled two 18-year-olds found in separate alleys in August 2009, prosecutors said. Kiara Windom, of Harvey, was found in Chicago Aug. 3, 2009, and Chicagoresident Kimika Coleman was found in Blue Island 24 days later.

Authorities say Pierce also killed Mariah Edwards, 17, a neighbor reported missing in July. Her remains have not been found, but a recording of Pierce allegedly having sex with her was recovered. Pierce allegedly told police she was beaten to death, put in a garbage bag and “”dumped”” in a spot he refused to reveal, court records show.

Investigators do not know whether there are other victims but are exploring that possibility, Cook County State’s Attorney Anita Alvarez said. Pierce met Windom and Coleman through phone chat lines and knew Edwards from the neighborhood, she said.

“”We’re charging him with three murders today, and there appears to be somewhat of a pattern here, and so … we’re looking to see if there’s … anyone else out there that could possibly have been a victim,”” she said.

Records show authorities questioned Pierce the day after Coleman’s body was found and that video evidence contradicted part of his statement. However, his DNA was not obtained until after he allegedly raped the girl in August, authorities said. He has been in jail on sex assault charges ever since.

Phone records showed Pierce spoke with the first two victims around the time of their deaths, and DNA found on their bodies matched his, court records show.

A friend of Pierce’s allegedly told police he knocked on Pierce’s door about an hour before Coleman’s body was found and Pierce called out, “”Let me finish this and I’ll call ya,”” court records show. Pierce later admitted he was with Coleman that night, records show.

The case took a turn almost exactly a year later, when a 15-year-old girl told police she was choked and raped by “”Sonny”” after he called her Aug. 12 and asked her to come over “”for five minutes,”” according to court records.

The girl told police Pierce forced her into his bedroom, choked her with his right arm and raped her on a mattress, records show. Police searched the apartment later that month, seizing the computer the girl said was playing music on during the attack.

On the computer, investigators say they found videos of Pierce sexually assaulting women, including a “”lifeless”” woman they identified as Edwards.

After police showed Pierce the video of Edwards on April 11, he admitted he invited her to his apartment intending to sexually assault her in front of several other men, court records show.

Pierce then told police he and the men beat Edwards during the sexual assault, put her body in a garbage bag and dumped it, records show. He refused to say where, court records show. Alvarez said authorities were not sure if there were other men involved.

Edwards’ family has belonged to the Apostolic Assembly Church of Jesus Christ on Chicago’s Far South Side for many years, said Pastor Jerry Jones. He said he knew Mariah Edwards since she was a baby and described her as “”very outgoing and gregarious.””

Windom was getting her GED and wanted to follow her sister into nursing, said her mother, Hallena Johnson.

“”I want him to get the death penalty,”” said Johnson, who wept as she saw Pierce’s face for the first time on a TV news broadcast Wednesday. “”He doesn’t deserve to be walking around anywhere. He doesn’t belong anywhere but in hell.””

A table in Johnson’s living room is covered with photographs of her daughter. On her bedroom wall, yellowed tape holds up a makeshift shrine, another photograph, a poem Kiara wrote and a red velvet glove that belonged to the young woman.

Pierce’s mother, Esther Pierce-Pearson, lived next door to her son in low-rise block apartments on Vincennes Avenue in Blue Island, across the street from the apartment complex where Edwards lived with her family.

“”He’s the child of my womb. I think I would know if my child was a murderer,”” she said.

Pierce called his mother from jail while she was being interviewed by a WGN-TV reporter. Pierce told WGN he was guilty only of having consensual sex with too many women.

Coleman’s mother, Kimberly, said Wednesday she was always confident her daughter’s killer would be caught.

“”He’s a sick individual,”” she said.

Kimberly Coleman, 45, said she often told her daughter, a senior at Sullivan House Alternative High School, to stop talking on phone chat lines.

“”I just never thought it would lead to this,”” Coleman said.

She said she’ll never be able to completely forgive Pierce.

“”I have a mustard seed of forgiveness for Sonny Pierce,”” she said, holding her fingers centimeters apart. “”None of this will bring my daughter back, but I’m just glad she isn’t another cold case and another unidentified statistic swept under the rug.””