BERKEL EN RODENRIJS, NETHERLANDS (BNO NEWS) -- The head of mental health clinics in the Dutch capital of Amsterdam was shot dead on New Year's Day while walking his dog near his home, officials said on Thursday. No arrests were immediately made and a motive was unknown.

The incident happened at approximately 7:15 p.m. local time on Wednesday when Rob Zweekhorst, the head of mental health and addiction care provider GGZ inGeest, was walking his dog near his home in Berkel en Rodenrijs. The town is located about 6 kilometers (3.7 miles) north of the port city of Rotterdam.

"Police received a call of a person shot at approximately 7:15 p.m. When officers arrived at the scene they found an injured man," a police spokesperson said on Thursday. "First responders attempted to resuscitate the man, but in vain. The man, a 44-year-old resident of Berkel en Rodenrijs, died at 7:45 p.m."

Witnesses reported seeing Zweekhorst being shot before the lone gunman fled the scene, the spokesperson said, adding that several witnesses were taken to a police station to be heard. "Police are investigating the case. Specialists are at the scene to search for evidence and officers are speaking with residents in the neighborhood," police said.

GGZ inGeest, which is a member of the Dutch Association of Mental Health and Addiction Care (GGZ Netherlands), said it was shocked by Zweekhorst's murder. "Rob was head of administration, service and management at our institution. We wish the family and friends of Rob all the strength in this difficult time," the organization said in a brief statement.

GGZ inGeest provides a range of specialist mental health services at its fourteen locations in and near Amsterdam.

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Apparently, someone has mental health issues that remain unaddressed.