NORFOLK, Va. -

Two suspects are being sought in the fatal assault of an Old Dominion University student.

Norfolk police tell media outlets that 20-year-old Paul Johnson died Sunday afternoon, about 13 hours after he was hit in the head while walking along a street.

Police have obtained warrants charging 21-year-old David William Grimm Jr. with second-degree murder. The second suspect, 20-year-old Christopher Chase Johnson, is charged with misdemeanor assault.

Police say Paul Johnson wasn't related to Christopher Chase Johnson.

Old Dominion President John R. Broderick says in a letter to students that Paul Johnson was a sophomore majoring in mathematics.