A former Vancouver political staffer has admitted to sexually assaulting four girls, one as young as six years old.

Ibata Noric Hexamer, 44, who reportedly once worked for the Vancouver municipal COPE party, was picked up by police in 2010 for a series of violent attacks dating back 15 years. According to other reports, Hexamer also worked for the NDP during the 2006 federal election.

On April 1, 1995, Hexamer approached a 13-year-old girl as she walked through the playground of Lord Nelson Elementary. He told her he had a knife, then dragged her to an outdoor stairwell at the school and sexually assaulted her.

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Through DNA evidence, police linked Hexamer to two other sexual assault cases: one in 2007 involving two 14-year-old girls in Delta, B.C., and a 2009 Surrey case in which a six-year-old girl was assaulted while her 12-year-old brother and his friend stood helplessly nearby.

Hexamer was charged with 23 offences, including sexual assault, sexual assault with a weapon and unlawful confinement.

He pleaded guilty Friday to six charges, and the Crown dropped the other 17, CTV reports.

Hexamer is scheduled to be sentenced in October.