A man who was previously charged in connection with the disappearance of a Dartmouth woman has now been charged with second-degree murder in her death.

Karen Lee MacKenzie was last seen alive in the Highfield Park area of Dartmouth on Feb. 25, 2018. The 40-year-old woman was reported missing to police on March 3, 2018.

Halifax Regional Police first arrested Owen Patrick Nelson on March 13, 2018. He was charged with interfering with human remains, assault, and two counts of breach of probation, in connection with MacKenzie’s disappearance.

Owen Patrick Nelson was arrested a second time at a home in Cole Harbour, N.S., early Wednesday morning.

Police say the 43-year-old Dartmouth man now faces a charge of second-degree murder in connection with MacKenzie’s death, as well as the charge of interfering with human remains.

The other charges have been dropped.

Halifax Regional Police Supt. Jim Perrin wouldn’t say what led police to lay the second-degree murder charge more than a year after Nelson’s initial arrest.

“There’s been ongoing collaboration and consultation, I should say, with the Public Prosecution Service, and just in the recent weeks we were satisfied that we were able to move forward with the charge and we did that today,” said Perrin during a news conference Thursday.

Perrin confirmed that Nelson and MacKenzie knew one another, but wouldn’t elaborate on their relationship.

He also confirmed that, despite conducting a number of searches in the Halifax Regional Municipality, Hants County, and Lunenburg County last year, MacKenzie’s remains have never been found.

“Unfortunately we didn’t recover Miss MacKenzie’s remains during those searches,” said Perrin. “We’re hopeful that we will get some information that leads us to where her remains are.”

Anyone with information about the case is asked to contact Halifax Regional Police.