Boston Police Commissioner Ed Davis will testify Thursday before the House Homeland Security Committee on the marathon attack and ask lawmakers for increased security funding, including for more surveillance cameras.

“Images from cameras do not lie. They do not forget,” Davis will say, according to prepared testimony obtained by The Associated Press. “They can be viewed by a jury as evidence of what occurred. These efforts are not intended to chill or stifle free speech, but rather to protect the integrity and freedom of that speech and to protect the rights of victims and suspects alike.”

Davis will also express concerns about protecting civil liberties in a time of heightened security.

“I do not endorse actions that move Boston and our nation into a police state mentality, with surveillance cameras attached to every light pole in the city,” Davis will say. “We do not and cannot live in a protective enclosure because of the actions of extremists who seek to disrupt our way of life.”

Davis will launch the first day of congressional testimony on last month's terror attack, with Congress expected to press Davis and other witnesses about the government's response to a tip from Russian authorities about suspect Tamerlan Tsarnaev before the attacks. They will also likely grill law enforcement officers about the manhunt for Tamerlan's brother, Dzhokhar, which shutdown much of Boston for a full day last month.

Speaking with reporters Wednesday at Logan Airport before heading to Washington, Davis said he expects a thorough inquiry into what Boston police officers knew before, during and after the attack.

“Our job is to prevent these things,” Davis told the Boston Herald. “So when something like this happens, you have to look at every single item, everything that we did in preparation so we can ensure that this doesn’t happen again.”

“You never know what members are going to ask, what questions,” Rep. Bill Keating (D-Mass.) told the Herald. “This was meant to not only take a pulse about what happened, but also so we’re not waiting for months and then going back again if we can learn some things now that we can share with federal and state officials.”