Police in Long Beach, California, appear to have thwarted a mass shooting by arresting a hotel cook who had amassed an astonishing cache of powerful firearms and had well-laid plans to carry out a gun rampage throughout the hotel.

Rodolfo Montoya, 37, was picked up at his home in Huntington Beach on Tuesday. The previous day he had allegedly confessed to a fellow worker at the Long Beach Marriott that he planned to carry out the attack as a revenge act for a grudge he bore the company.

The fellow worker immediately sounded the alarm. In ensuing searches, police discovered the pile of firearms that included pistols, two assault rifles of the sort used in several recent mass shootings, a pump-action shotgun and thousands of rounds of ammunition.

The alleged foiled plot to attack the Marriott once again puts the spotlight on America’s lax gun laws. A key question being addressed by detectives is how Montoya came to amass such a stash of deadly weapons without drawing attention to himself.

It is thought that he had no prior criminal record, which would have freed him to buy some firearms over the counter. Even so, several of the weapons in his possession are illegal in California including the assault rifles and investigators will try to find out whether he obtained them by nefarious means or out of state.

Robert Luna, the police chief of Long Beach, addressed the guns issue on Tuesday. He recognized a “serious conversation” was taking place across the US about access to lethal weapons. “There is no question that as a country and as a community, we are having a conversation about that and need to do more, and we should be doing more,” he said.

Donald Trump promised to tighten background checks on the sale of firearms in the wake of the pair of mass shootings in El Paso, Texas, and Dayton, Ohio, earlier this month that killed 31 people. But in a pattern that has been seen before he subsequently walked back his pledges having been lobbied by the National Rifle Association.

But Trump is likely to remain under pressure over gun policy given the spate of arrests being made across the country of individuals apparently motivated to carry out copycat attacks after El Paso and Dayton.

Montoya’s arrest in California brings to at least seven the number of mass shootings or white supremacist plots that police claim to have intercepted since the Texas rampage.

They included Conor Climo, 23, from Las Vegas who allegedly planned to attack Jews and a gay bar in the city. Climo is reported to have told police that he belonged to a neo-Nazi group.

Three planned gun rampages were apparently thwarted last week alone in separate incidents in Connecticut, Florida and Ohio.