(CNN) In 1991 Denise Sharon Kulb's body was found in a woodsy, undeveloped cul-de-sac in suburban Philadelphia after being missing for over three weeks.

It took 28 years, but authorities have finally arrested someone in her killing -- her then-boyfriend, thanks in part to new technology and a pair of socks.

Theodore Dill Donahue was arrested for the 1991 slaying of his girlfriend.

Theodore Dill Donahue, 52, was arrested in Kulb's death after police gathered new evidence and interviews, Philadelphia District Attorney Larry Krasner and the Pennsylvania State Police said Tuesday

Donahue was charged with murder, abuse of a corpse, tampering with evidence, obstruction of justice and false reports to police. He has pleaded not guilty.

Authorities began to reinvestigate Kulb's killing in 2015, using new investigative tools to rebuild the case, Krasner said.

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