ANCHORAGE, Alaska — A former Anchorage doctor convicted of sexually abusing four children will serve at least 23 years in prison.

Clifford Merchant was given a 51-year sentence with eight years suspended Friday after he pleaded guilty to sexual abuse of a minor and child pornography charges. He has been ordered to serve at least 23 years behind bars before he’s eligible for parole.

Authorities began investigating the 69-year-old Merchant in 2014, when a 12-year-old girl reported that he had touched her inappropriately. Investigators eventually identified three other victims, all under age 13.

Prosecutors said in court documents that the girls were abused at Merchant’s home, in his airplane and at his cabin at Shell Lake near Skwentna. The alleged abuse occurred between 2001 and 2013.

Merchant was released on $75,000 in bail after his initial arrest and was later accused of hiring an FBI informant to kill one of the victims, according to court documents.

The informant had posed as a contract killer and met with Merchant twice to discuss prices but Merchant eventually called off the plan, the documents said.

As part of his plea deal in April, Merchant also pleaded guilty to violating probation in connection with the alleged murder-for-hire plot.

A relative of one victim said she was satisfied with the sentence.

She called the damage Merchant did to her family “so wide and so vast,” according to a victim impact statement.