The head of the state environmental police, a former state trooper who once served as Gov. Charlie Baker's campaign driver, has been abruptly suspended without pay, officials have confirmed.

Col. James McGinn, who was handed the $132,000 a year post by Baker despite having no environmental experience, was suspended effective Oct. 4 but officials declined to cite the reasons for the suspension.

Sources said McGinn was asked to resign but he refused, and subsequently was put on unpaid suspension.

"Col. McGinn is currently suspended without pay pending the completion of an internal review of operational issues at the Massachusetts Environmental Police," said Peter Lorenz, spokesman for the state office of environmental affairs.

Officials said Lt. Col. Anthony Abdal-Khabir has taken operational command and control of the department.

McGinn has had a stormy tenure at the environmental police. His promotions and demotions of key personnel drew scrutiny.