St. Louis police believe former volleyball player Megan Boken was killed during an attempted robbery as authorities said they had no strong leads in the murder of the 23-year-old Illinois resident.

Boken, who played volleyball at the University of St. Louis and graduated from the school in 2011, returned to the area Saturday for an alumni game when she was shot and killed while inside her parked car near an apartment complex in the Central West End neighborhood of St. Louis.

While St. Louis Police Chief Dan Isom said authorities believe Boken was murdered during a botched robbery, authorities have "no concrete leads" into why killed the standout volleyball player, the St. Louis Post-Dispatch reported.

"We're really here to make a public appeal and ask for more information," Isom told a press conference Monday afternoon.

St. Louis police are offering a $10,000 reward to anyone with information on Boken's killer, according to the Wheaton, Ill., Leader. Boken is a native of Wheaton, a suburb of Chicago.

Despite initial speculation that Boken knew her killer, that theory has since been shot down after that possibility first surfaced from Kara Bowlin, press secretary for St. Louis Mayor Francis Slay.

St. Louis police spokesman Dan Marzullo said there was no indication Boken was familiar with her murderer.

"We don't know whether the suspect was in the vehicle and got out and shot her or if he opened the door and shot her. There are conflicting statements," Marzullo told the Associated Press. "We are investigating this as an attempted robbery."

In a statement, Boken's family called her "a wonderful and beautiful human being loved by everyone she met.

"The family and the community are devastated by this senseless tragedy and the family would like to thank everyone for their outpouring of support," they said, according to Fox News.

Boken's former coach and teammates remembered the 23-year-old more for her personality than her athletic achievements.

"There's just not anybody that played SLU volleyball during my 7 years that isn't reeling right now," said her coach, Anne Kordes.

"She'll be remembered as an unbelievable teammate. She played on championship teams, but she was that teammate that kept everybody together," said St. Louis University Athletic Director Chris May. "She's everything you want in a student athlete: wonderful student, a great athlete and an even better person."

Boken's friend, Sarah Entzeroth, described the former volleyball player as "sweet, social and funny," according to KSDK.

"None of our lives will ever be the same," Entzeroth said. "She was my best friend and she is one of the greatest people I've ever met ... She was at my apartment staying with me this weekend and we walked to our separate cars and at 2 o'clock and we will never see her again."

Authorities asked anyone with information on Boken's killing to call CrimeStoppers at 1-866-371-8477.