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Authorities in Wisconsin arrested and charged a teenager in what they called the "calculated" double homicide of a university doctor and her husband last week, police said Saturday.

Police at the University of Wisconsin-Madison said Ali'jah J. Larrue, 18, was booked on two counts of first-degree intentional homicide in the killings of Dr. Beth Potter and Robin Carre.

The announcement of Larrue's arrest came one day after police said that another teenager alleged to have been an accomplice, Khari Sanford, 18, was also taken into custody on suspicion of being a party to the killings of Potter and Carre.

A jogger found the bodies of Potter, 52, and Carre, 57, in a ditch early Tuesday at the University of Wisconsin Arboretum, an ecological research facility with more than a dozen miles of trails.

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Carre was pronounced dead at the scene. Potter died at a hospital.

Police said that Sanford was "known" to the victims' family and that their killings appeared targeted.

"We believe that this was not a random act," authorities said in a statement. "It was calculated, cold-blooded and senseless — and we will continue to do all we can to bring justice to Robin and Beth, their family, and their loved ones."

NBC affiliate WMTV reported that Sanford attended the same high school as the couple's daughter.

In a statement, the University of Wisconsin said Potter was an associate professor in the Department of Family Medicine and Community Health. She pioneered occupational health and chronic pain programs and taught and mentored hundreds of family medicine students, it said.

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"She was wise, warm and always supportive," said a colleague, William Schwab. "There are so many in our department whose lives have been touched by Beth; her loss will weigh heavily within us."

Carre was an independent educational consultant and soccer coach, according to his website.

Larrue and Sanford are expected to make initial court appearances early this week, The Associated Press reported. It wasn't immediately clear whether they have lawyers.