A former employer says a janitor, allegedly caught with a stash of weapons in Ossining Sunday, was fired earlier this year for threatening a co-worker at a local nursing home.Police say when they pulled over 48-year-old Tarrytown resident Jose Custodio they found six powerful assault weapons, thousands of rounds of ammunition, knives, two bulletproof vests and a police scanner. Bruce Bradigan is the CEO of the Bethel Nursing Home where Custodio worked for 25 years as a housekeeper. He says Custodio was fired in February for threatening another employee. Custodio, who is being held at Westchester County Jail, is due back in Ossining Village Court Tuesday. If convicted he could face up to six years behind bars.