(Reuters) - A grand jury indicted two former Virginia Tech students on Tuesday for first-degree murder in the death of a 13-year-old girl, a prosecutor said.

The suspects, David Eisenhauer, 18, of Columbia, Maryland, and Natalie Keepers, 19, of Laurel, Maryland, were indicted for the January slaying of Nicole Lovell, Montgomery County prosecutor Mary Pettitt said in a statement.

The middle school student's body was found stabbed by a North Carolina roadside about 90 miles south of Blacksburg, her hometown, following a four-day search. Lovell's death shocked the area and sparked national attention.

A Montgomery County grand jury indicted Eisenhauer on charges of first-degree murder, abduction and concealing a body. Keepers was indicted on charges of being an accessory before the fact to first-degree murder and concealing a body.

Police in Blacksburg, in southwest Virginia and home to Virginia Tech, have said Eisenhauer and Lovell had become acquainted before her disappearance. Eisenhauer, who was a member of the Virginia Tech cross-country team, took advantage of the relationship to abduct and kill her, police have said.

Authorities have not disclosed a motive, but two law enforcement officials told The Washington Post that Eisenhauer had an inappropriate relationship with Lovell.

A friend said Lovell had hoped to run away with Eisenhauer and start a family, the newspaper has reported.

If convicted, Eisenhauer faces life plus 15 years in prison, and Keepers could be sentenced to life plus five years. They are being held without bond, and their trials are set for March.

(Reporting by Ian Simpson; Editing by Steve Orlofsky)