Boston Marathon Explosions Photo Package

Female DNA was found on bomb components used in the attack this month on the Boston Marathon, a source familiar with the investigation confirmed to Fox News, though the source cautioned that it is too early to draw hard conclusions from that evidence.

“No one should expect that the investigation is over,” the source told Fox News in confirming the development first reported by the Wall Street Journal, adding that it is just one piece of evidence that investigators are looking at.

The revelation about female DNA came on the same day that the FBI went inside the Rhode Island home of bomber Tamerlan Tsarnaev’s widow’s parents, and the nearby family of a man identified as his mysterious mentor hired a family spokesman to keep the media at bay.