Unannounced, random metal detector checks will continue at Lakeland High School after a string of violent threats there and at two other district schools last week, an administrator says.

Extra city and fire officers were to patrol King’s Fork High School Friday in response to threats of a “shoot out” and explosion.

The threats have apparently prompted parents to keep children home from school. On Friday, 14 percent of Lakeland, 31 percent of King’s Fork Middle, and 65 percent of King’s Fork High School students were absent, while usual rate is 6 to 7 percent, according to district spokeswoman Bethanne Bradshaw.

The shooting threat was contained in posts on social media website Twitter that were reported to administrators Thursday morning, principal Suzanne Rice wrote in a letter to parents.

The school was placed on Code Yellow lockdown, and metal detector checks were performed on all students and their belongings, according to Kevin Alston, district assistant superintendent for instructional services.

On Wednesday morning, according to Rice, reports were received of a message written on a stall in the girls’ bathroom: “KF will be blown up on April 26.”

Meanwhile, a message written on a boys’ bathroom wall was reported to King’s Fork Middle School administrators just before dismissal Thursday, according to a recorded voice message to parents and staff.

The threat stated “the school would be blown up,” according to the recorded message, and police and fire investigators were called to assist in an ongoing investigation.

The first incident was at Lakeland High School on Monday, when a staff member found a bomb threat inside a bathroom stall, according to a letter to parents by Principal Thomas Whitley.

The fire marshal conducted a sweep of the school before it was declared safe to hold classes Tuesday.

Then on Tuesday, a Code Yellow occurred at Lakeland after a bomb threat was found on a different bathroom wall shortly before lunch. The code lasted about an hour as State Police searched the school.

Earlier in the day, the school had been placed on lockdown for a regularly scheduled visit by the Suffolk Police Department and its drug dogs.

On Wednesday at Lakeland, the occupants of every fourth bus were required to pass through a metal detector, Alston stated.

Random metal screenings are part of the district’s crisis management plan and will be ongoing, he added. One was conducted at Lakeland at March 28 with every ninth bus checked.

A restroom policy is also in effect at Lakeland and “will continue as long as deemed necessary,” Whitley stated.

“Students are required to sign in and out of the restroom throughout the day (and) they are not allowed to carry any bookbags or backpacks into the restroom,” he wrote, adding the metal screenings will continue “for the remainder of the year.”