Ukrainian police say they have arrested a suspect in the slaying of a lawyer whose death sparked demonstrations outside the national police headquarters in Kiev.

Iryna Nozdrovska's body was found in a river on Jan. 1. Media reports said the 38-year-old lawyer had been stabbed repeatedly.

She had mounted a campaign to make sure the man convicted of running down and killing her sister with his car remained in prison. The man is related to a prominent Kiev judge. A court in December rejected his appeal to be released from prison and Nozdrovska went missing two days later.

A spokesman for the Interior Ministry, Artem Shevchenko, was quoted as saying Monday by the Interfax news agency that a suspect had been arrested in the case. He did not elaborate.