UPDATED 08/23/12 – 6:13 p.m.

WHEATON, Ill. (CBS) — St. Louis police have arrested two 18-year-old suspects in the murder of Wheaton volleyball star Megan Boken, who was gunned down in St. Louis last weekend.

St. Louis Police Chief Dan Isom said charges would be presented to the St. Louis Circuit Attorney’s office on Friday.

“We are confident, based on the evidence that we have, that we have the killers of Megan Boken in custody,” Isom said.

Isom said the shooting appeared to be the result of a robbery, and the two suspects are being investigated for other robberies in the area.

One of the suspects was arrested Thursday morning, the other was arrested Thursday afternoon.

Boken, 23, was gunned down in broad daylight while sitting in her car in the Central West End neighborhood of St. Louis on Saturday. The former St. Louis University volleyball player was visiting her alma mater for an alumni volleyball game.

“Nothing irritates me more, nothing worries me more when I go to sleep at night and when I wake up every morning than to think about these thugs that are out there, trying to victimize innocent people in our city,” St. Louis Mayor Francis Slay said.

Boken’s family, friends, and former teammates gathered Thursday morning to pay their final respects at St. Michael Catholic Church in Wheaton. The family declined comment after it was reported two suspects would be charged.

A 2011 SLU graduate, Boken was in St. Louis for a reunion game for former volleyball players, scheduled to take place about two hours after she was killed. When she didn’t show up, her teammates knew something was wrong.

David Welkner had known Boken since their freshman year of college.

“She was everything. She was one of my best friends. She was always happy. She was always in a pleasant, great mood; always helped me out,” Welkner said, “and she’s missed dearly.”

CBS 2’s Suzanne Le Mignot reports tears fell, and hugs were shared as Boken’s friends, family, and teammates came together to celebrate her life.

“We’re going to miss her a lot,” said Boken’s friend, Tory Rezin. “She was the nicest person.”

Family friend Sue Ferraro described Boken as a “special angel that we’re going to miss forever.”

“She was just a phenomenal person. She was great. It’s just a tragedy that something like this – so senseless, stupid – would happen to such a wonderful person,” Ferraro said.

Students from St. Francis High School in Wheaton attended the funeral. Boken went to St. Francis; she was also an All-State volleyball player in Wheaton.

Boken’s friend Tori Vandeleur said, “When she got on the court, she was one of the most serious players I’ve ever seen. She knew the game of volleyball very well, and she was a great player, and great athlete.”

As for the arrests of two people in Boken’s murder, her best friend, Bridget Fonke, said, “We’ll see how that pans out, but that makes everyone feel better and, you know, just for the family, I know they would appreciate knowing, and that will help a lot.”

The gunman who killed Boken has been described as a black male, with a medium complexion, and a thin build. He is 5’8″ to 5’10”, with short hair, and was last seen wearing a grey charcoal shirt, khaki pants, and white tennis shoes..

The reward for information leading to the arrest of Boken’s killer has increased to $31,000. Police would not say if the reward prompted a tip that led to the arrests.

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