The other, 33-year-old Danny Provencal, was serving a seven-year sentence for various offenses, including arson, police said.

CNN: STORY HIGHLIGHTS

The construction site has been vandalized several times, including an arson attack in 2010 and "not welcome" spray-painted on a sign announcing the project.

CNN: Tennessee mosque set to open Friday

From 1989 to the end of September, the Virginia DNA databank helped police solve 107 rape cases, 28 homicides, 10 rape homicides, 90 burglaries and breaking and entering cases and 14 other crimes including auto theft, drive-by shooting and arson, Ferrara said.

CNN: graphic

Tuesday's announcement comes a day after a mosque in Joplin, Missouri, burned to the ground in a fire that federal agents are investigating as a possible arson, and two days after an alleged white supremacist gunman killed six Sikhs and wounded three others, including a police officer, near Milwaukee, Wisconsin.

CNN: Tennessee mosque set to open Friday