MORGAN HILL -- Police have arrested a 61-year-old man on suspicion of killing his live-in girlfriend and dumping her partially-clothed body near railroad tracks behind a mobile home park, the city's first homicide of the year.

Police issued a news release Monday classifying the death of the 46-year-old Bertha Paulson as a domestic-violence homicide.

Police arrested Michael Sheppard, 61, of Morgan Hill, early Sunday morning on suspicion of murder and felony domestic violence. Sheppard and Paulson got into an argument and then he physically assaulted her, police say. Paulson lost consciousness due to the injuries, according to police.

Her body was found Saturday morning around 9 a.m. by a resident of a mobile home park at 17880 Monterey Road, according to Sgt. Shane Palsgrove. Her pants had been pulled down around her knees, and her upper body was draped in a jacket.

Sheppard and Paulson lived in the mobile home park near where her body was located, police said.

"Morgan Hill Police Detectives worked alongside crime lab criminalists for hours on end to identify and apprehend the suspect and bring justice to the victim and her family," Morgan Hill Police Chief David Swing said in a statement. "I extend my deepest sympathies to the family and my strongest praise to the men and women who worked this case and brought it to a just conclusion."

Anyone with information about the incident is encouraged to contact Morgan Hill Police Department detective Jason Broyer at 408-779-2101 or the anonymous tip line at 408-947-STOP (7867).

Contact Mark Gomez at 408-920-5869. Follow him on Twitter @MarkMgomez