COLUMBIA HEIGHTS, Minn. - A man has been arrested in connection with the death of a woman believed to be his companion, according to the Anoka County Sheriff's Office.

A 29-year-old St. Paul woman was found deceased in the back of a vehicle on the 4200 block of 5th Street NE in Columbia Heights just before 12:30 a.m. on Jan. 1, according to the sheriff's office.

Authorities say the woman was significantly injured. The official cause of death has not yet been determined by the medical examiner's office.

The investigation led to the arrest of one murder suspect, a 35-year-old Fridley man believed to be her companion, deputies said. The man was arrested on Jan. 2 at about 6:40 p.m. in Fridley with help from the Minnesota State Patrol, and Fridley and Columbia Heights police.

The suspect has been booked in Anoka County Jail for second-degree murder. His brother has also been arrested for aiding an offender, according to the sheriff's office. Neither has been charged.

Investigators say the murder likely took place on Fifth Street NE in Fridley, even though the body was found in Columbia Heights. The case is under investigation.