A 27-year-old woman was allegedly sexually assaulted by a man she didn't know while she was moving out her apartment in Annadale, Fairfax County police said.

The sexual assault reportedly happened Tuesday around 3 p.m. in the 7900 block of John Adams Court, authorities said.

A 27-year-old woman was moving out of her apartment when a man approached her while she was going from the parking lot to her apartment. The man asked the victim if she needed help. According to authorities the woman thought this was suspicious because she did not know him.

An hour later, while she was in her apartment, the same man apparently came through the open door, grabbed her, stated he had a knife and told her to undress, according to police. The suspect then sexually assaulted the woman, police said.

According to authorities a neighbor heard the victim screaming and ran to the apartment to help. The suspect pulled the 35-year-old woman down to the ground by her hair and then ran off in the direction of Rectory Lane.

Burhan Nurhussein Ahmed, 20, of Annandale, was arrested around 3:45 p.m. Wednesday. He was taken in for questioning and will be charged with abduction with intent to defile, burglary with intent to defile, object sexual penetration, forcible sodomy, aggravated sexual battery and attempted object sexual penetration.

A mugshot is not available at this time.

Both victims were taken to the hospital with non-life-threatening injuries, authorities said.

If you have information about this crime, please contact Detective T. Struthers at 703- 246-7800. You may also contact Crime Solvers electronically by visiting http://www.fairfaxcrimesolvers.org or text-a-tip by texting “TIP187” plus your message to CRIMES(274637)**, or call Fairfax County Police at 703-691-2131 .