Washington: A former sheriff's deputy who did not enter a high school in Parkland, Florida, during a massacre in February receives more than $US100,000 ($130,000) in an annual pension, the state has revealed, triggering outrage among parents of slain students and renewed accusations of cowardice.

The Florida Department of Management Services said in a statement on Wednesday that Scot Peterson began receiving his $US8702.35 monthly pension in April after Broward County Attorney-General Michael Satz found no charges against him that would force him to forfeit his pension.

"The department will continue to monitor the ongoing investigation by the Florida Department of Law Enforcement and will continue to follow the law," spokeswoman Nina Ashley told The Washington Post in the statement.

Peterson took a defensive position outside Marjory Stoneman Douglas High School and did not enter the building as a gunman killed 17 people, videos released by police showed.

US President Donald Trump called a Peterson a "coward" and Broward County Sheriff Scott Israel said he was "disgusted" and "just demoralised" by his actions. Peterson resigned on February 22, eight days after the killings, amid intense public scrutiny.