A University of Wisconsin physician and her husband whose bodies were found in a ditch were shot dead, cops revealed as they arrested a second teenage suspect.

Police said Saturday that they arrested Ali'jah Larrue, 18, on Friday night for the double-homicide of Dr. Beth Potter, 52 and Robin Carre, 57.

A jogger found the bodies of the husband and wife last Tuesday in a ditch at the university's arboretum, a research and popular recreational area.

Larrue was booked into jail on two counts of party to the crime of first-degree intentional homicide.

UW police spokesman Marc Lovicott said Sunday that Larrue is an acquaintance of the other suspect, Khari Sanford, 18, who was arrested earlier Friday and booked on the same charges.

A second teenage suspect Ali'jah Larrue (left), 18, has been arrested for the double homicide of a University of Wisconsin physician Dr. Beth Potter, 52 and her husband Robin Carre, 57, whose bodies were found in a ditch last Tuesday. Khari Sanford (right), 18, was arrested earlier Friday

'We are confident these are the two guys,' Lovicott told The Associated Press, although the investigation remained active.

Lovicott said the couple had been shot at the arboretum sometime overnight before their bodies were found, but that police were not ready to discuss a motive.

Police have said the couple were targeted and that Sanford was known to the victims' family.

UWPD earlier described the killings as 'calculated, cold-blooded, and senseless'.

The department declined to confirm to DailyMail.com the nature of Sanford's relationship to the family at this stage.

However, sources told 27 News that Sanford is acquainted with one of the children of the victims.

Dr. Potter worked at the Wingra Family Medical Center, run by the UW-Madison Department of Family Medicine and Community Health and Access Community Health Centers and Mr Carre Mr Carre headed up a Madison youth soccer club

A jogger found the bodies of the husband and wife last Tuesday in a ditch at the university's arboretum, a research and popular recreational area. Pictured: Police at the scene were the couple's bodies were found

That child's Facebook page features a video of the suspect playing football for Madison West High School.

The suspects have not been formally charged but are expected to make their initial court appearances early this week, Lovicott said.

He did not know if they have attorneys who could speak on their behalf.

Authorities were led to the suspects through 'really good police work and help from our community,' Lovicott said.

Police have said the couple were targeted and that Sanford was known to the victims' family

Police were at the scene were the couple's bodies were found

He said people got in touch with police and shared information.

'That definitely played a part,' Lovicott said.

Dr. Potter worked at the Wingra Family Medical Center, run by the UW-Madison Department of Family Medicine and Community Health and Access Community Health Centers.

She also was medical director of UW Health's Employee Health Services.

Police said Sanford is 'known to the family' and that 'this was not a random act'. The UWPD declined to confirm to DailyMail.com the nature of Sanford's relationship to the family at this stage

Sources told 27 News that Sanford is acquainted with one of the children of the victims

According to a tribute on the medical school's website, Dr Potter's ability to speak both French and Spanish 'brough clarity and comfort to the diverse patient population she served'.

'In addition to being a wonderful family physician and highly respected teacher, Beth was a dedicated clinical leader,' William Schwab, M.D., the interim chair of Potter’s department, said in a statement.

Mr Carre headed up a Madison youth soccer club.

His professional consulting work involved helping high school students best prepare themselves for college admissions.

The couple are survived by three children in their teens and twenties.