After Sunday's attack at the Route 91 Harvest Festival in Las Vegas, Caleb Keeter of the Josh Abbott Band had a change of heart regarding gun control and the 2nd Amendment.

Keeter is a guitarist in the band. They played at the country music festival attacked by a gunman from the 32nd floor of the Mandalay Bay Resort.

Keeter posted on his Twitter account Monday morning.

"I've been a proponent of the 2nd Amendment my entire life. Until the events of last night. I cannot express how wrong I was," he says in the Tweet. "We actually have members of our crew with CHL (concealed handgun) licenses and legal firearms on the bus. They were useless."

The gun lobby uses the good guy with a gun theory after mass shootings. Keeter was able to see firsthand that more guns couldn't prevent Sunday's tragedy.

"A small group (or one man) laid waste to a city with dedicated, fearless police officers desperately trying to help, because of access to an insane amount of fire power. Enough is enough."

"We need gun control RIGHT. NOW," Keeter concluded. "My biggest regret is that I stubbornly didn't realize it until my brothers on the road and myself were threatened by it. We are unbelievably fortunate to not be among the number of victims killed or seriously wounded by this maniac."

His Tweet has drawn criticism from both sides of the gun control debate.

Keeter only responded to those who took issue with the reason for his change of heart by stating, "You are all absolutely correct. I saw this happening for years and did nothing. But I'd like to do what I can now."