FRANKLIN—The motive behind the murder of a 28-year-old Southampton County man appears to be robbery, the sheriff’s office reported Thursday.

Darrin Lee was fatally shot outside of his home in the Southampton Meadows mobile home park late on the night of Oct. 7.

Three Suffolk men, Darrin L. Robinson, 20; Bruce L. Boone, 18; and Dayquan Eley, 18, were arrested shortly after Lee’s murder. A fourth suspect, 21-year-old Shahon Cumbo of Franklin, was arrested in Chesapeake Tuesday after being located the U.S. Marshal Service.

Sgt. Wanda Covington, a spokeswoman for the Southampton County Sheriff’s Office, wrote in an e-mail that the connection between Cumbo and the other three suspects “is not yet clear.”

“It seems as if he was acquaintances with a few of them,” she wrote.

The family suspected the motive was robbery, but police remained quiet on the motive until Thursday.