Dallas police said they are trying to determine who hacked their website Thursday evening.
The police department website — www.dallaspolice.net — was offline for several hours in what police called a denial of service attack.
Police said they think an outside group was responsible for the attack and they are investigating who might be responsible.
Hackers also broke into the department's site in 2012 and accessed officer information.
The hacker group called Anonymous took credit for breaking into the Texas Police Association's website and publishing the names and address of hundreds of Texas police officers the week before the 2012 hack.
The department website was back online late Thursday night.
