A local sheriff’s office is investigating claims that three deputies on patrol at Marjory Stoneman Douglas High School failed to intervene when a gunman entered the Florida school and killed 17 people.

Coral Springs police officers who responded to the shooting that day said two deputies from Broward County were standing outside the building when they arrived, according to the South Florida Sun Sentinel. Broward County Sheriff Scott Israel said the department was investigating the claims. He plans to interview the two officers who lodged the complaint.

"If there is no wrongdoing in the part of our deputies, we’ll move on," Mr Israel told ABC. "If there is wrongdoing on the part of our deputies, we’ll handle it accordingly as I have for five years as sheriff."

The Coral Springs Police Department declined to comment on the claims, saying: “Any actions or inactions that negatively affected the response will be investigated thoroughly, and the information will be released officially.”

The news came shortly after a third officer, Scot Peterson, resigned after it was revealed that he had failed to engage the shooter. Video footage showed the deputy, who was assigned to patrol the high school, stood outside the building for upwards of four minutes while shots were fired, Mr Israel said.

Florida shooting – in pictures Show all 10 1 /10 Florida shooting – in pictures Florida shooting – in pictures Police arrest a suspect in connection with the shooting at the Marjory Stoneman Douglas High School in Parkland, Florida Reuters Florida shooting – in pictures Parents wait for news after reports of a shooting at Marjory Stoneman Douglas High School in Parkland, Florida AP Florida shooting – in pictures Anxious family members wait for news of students AP Photo/Wilfredo Lee Florida shooting – in pictures Students being evacuated from the school AP Florida shooting – in pictures Students being evacuated from the school Getty Florida shooting – in pictures People gather waiting for word from students AP Florida shooting – in pictures Parents waiting for news on their children AP Florida shooting – in pictures People gather at a hotel where students were taken after the shooting Getty Florida shooting – in pictures Florida Governor Rick Scott speaks to the media as he visits Marjory Stoneman Douglas High School following the shooting AFP/Getty Florida shooting – in pictures Dr. Igor Nichiporenko, Medical Director Trauma, left, and Dr. Evan Boyer, Medical Director, Emergency Services, speak about treating victims and the suspect at a press conference outside Broward Health North hospital AP

Broward Schools Superintendent Robert Runcie said at the time that he was “in shock and outraged” that Mr Peterson had not entered the school more quickly.

“It’s really disturbing that we had a law enforcement individual there specifically for this reason, and he did not engage,” he said. “He did not do his job. It’s one of the most unbelievable things I’ve ever heard.”

President Donald Trump also criticised the deputy, saying he was either a “coward” or had not properly responded to the shooting.

“He didn’t turn out to be too good, I will tell you that,” Mr Trump said at a conservative political conference. “He was not a credit to law enforcement.”

Donald Trump: Florida school deputy 'did a poor job' and lacked 'courage'

Two more deputies are being investigated over whether they mishandled warnings about the alleged gunman in the months before the shooting, according to the Sun Sentinel. The office was warned by neighbours as early as February of 2016 that the suspected gunman, 19-year-old Nikolas Cruz, “planned to shoot up the school”.

The FBI also admitted that they had failed to act on a tip from someone close to Mr Cruz, who reported concerns about the teenager’s “gun ownership, desire to kill people, erratic behaviour, and disturbing social media posts, as well as the potential of him conducting a school shooting,” according to an agency statement.