A convicted killer who twice escaped from his death row cell fought with guards to the end on Tuesday and stunned the authorities during his execution by spitting out a small handcuff key.

The inmate, Ponchai Wilkerson, mumbled, ''The secret, as of Wilkerson,'' as he spit out the key while lethal chemicals flowed into his body, said James Brazzil, a chaplain who was in the death chamber.

Seven minutes later, Mr. Wilkerson was pronounced dead. The authorities said they did not how he got the key.

Mr. Wilkerson, 28, had struggled with prison guards all day. Hours before the execution, guards had to use a Mace-like spray on him when he refused to leave his cell at a prison near Livingston for the 40-mile trip to Huntsville.