WASHINGTON Following yet another mass shooting in America, Sen. Chris Murphy (D-Conn.), who made gun control his cause after 20 children were among those killed in the 2012 attack at Sandy Hook Elementary School in his home state, pilloried his congressional colleagues for having done nothing to prevent such assaults.

Wasting no time responding to the shooting in Las Vegas Sunday night in which at least 58 people were killed, plus the gunman, and more than 500 hurt the deadliest such incident in modern U.S. history Murphy took to the Senate floor on Monday to speak about a growing fraternity of lawmakers who now represent areas where massacres have occurred.

I think there is an unintentional endorsement that gets sent to these mass murderers when after slaughter after slaughter, Congress does nothing, Murphy said. If the greatest deliberative body in the world doesnt do anything to condemn them by policy change, it starts to look like complicity.

The senator spoke about his constituents in Newtown, Connecticut, saying the pain from the shooting at the Sandy Hook school remains raw almost five years later. The hurt is deep, the scars are wide in Newtown, Murphy said, but they are made wider by the fact that this body ... has done absolutely nothing.

This is a growing fraternity, a tragic, awful fraternity: Members of Congress who represent states who have gone through horrific mass executions, he said. This silence has become unintentional endorsement. Its become a kind of sick complicity.

During his speech, Murphy called on his colleagues to at least have a conversation about gun control and explore why America was a laggard when it comes to protecting ourselves and our citizens.

Compassion is important, but it is not enough, he said.

Then-President Barack Obama characterized the Dec. 14, 2012, shooting at the Sandy Hook school as the worst day of his tenure in the White House. In remarks he made that day, he implored the nation to come together and take meaningful action to prevent more tragedies like this, regardless of the politics.

He kept pushing for action from Congress as did many other Americans, including those who lost children at Sandy Hook. But even a modest proposal to expand background checks for gun purchases went nowhere.

Wayne LaPierre, the chief executive officer of the National Rifle Association, responded to the shooting by calling for armed officers to be stationed at every U.S. school.

Earlier on Monday, Murphy issued a strongly worded statement imploring Congress to get off its ass and do something.

My heart goes out to the victims, their families, the first responders, and the entire Las Vegas community. Nowhere but America do horrific large-scale mass shootings happen with this degree of regularity, he said.

This must stop. It is positively infuriating that my colleagues in Congress are so afraid of the gun industry that they pretend there arent public policy responses to this epidemic, he said. There are, and the thoughts and prayers of politicians are cruelly hollow if they are paired with continued legislative indifference. Its time for Congress to get off its ass and do something.

Murphy has continually lambasted lawmakers for giving quiet endorsement to these murders and for providing thoughts and prayers without any action , following numerous mass shootings in recent years.

Six school staff members also were killed by shooter Adam Lanza in the attack at the Sandy Hook school. Lanza, who first killed his mother at their home, shot himself to death at the school.

This article has been updated with additional comments from Murphy and background on the push for gun control measures following the mass murder at Sandy Hook Elementary School.