About 1,600 firefighters remained on the scene Saturday of the Detwiler Fire, which Calfire investigators say was caused by firearms being used on public land.

A $2,000 reward has been offered for information about who was doing the shooting.

Calfire did not release information on suspects, saying only the incident remains under investigation.

The Mariposa County fire was 97 percent contained and covered 81,826 acres between Coulterville and Mariposa. Both towns were spared, but 63 residences, 67 minor structures and one commercial structure were destroyed. Damage was reported to 13 residences and eight minor structures.

The fire started shortly before 4 p.m. on July 16 at Detwiler and Hunters Valley roads, two miles east of Lake McClure.

Calfire issued a statement this morning saying, "Firefighters continued working the fire and continued to mop up and patrol lines. All fire lines are holding."

In Tuolumne and Calaveras counties on Thursday, firefighters responded to six vegetation fires. All were readily contained and the largest burned about three acres, according to Emily Kilgore, a fire prevention specialist with the Tuolumne-Calaveras Unit.

“Not all caused by lightning,” Cal Fire Tuolumne-Calaveras Unit staff tweeted at 6:40 a.m. Friday.

Thursday night, Calfire tweeted, “Good news #TwistFire is now 100% contained. Bad news is there are lightning strikes throughout the Unit. Minimal precip. Stay safe outdoors.”

Kilgore put together a list that showed eight fires broke out Thursday and the causes of all of them remained under investigation. Battalion Chief Matt Gilbert, in charge of fire prevention and law enforcement for the Tuolumne-Calaveras Unit, did not respond to requests for comment.

Afternoon and evening thunderstorms with potential for more lightning strikes are possible again today and Sunday, forecasters said.

Here are the fires that broke out Thursday in Tuolumne and Calaveras counties:

+ A house fire reported at 11:59 a.m. in the 21500 block of Cedar Springs in Twain Harte displaced a total of five people. Contained at 12:53 p.m. Cause is under investigation.

+ A vegetation fire reported at 2:34 p.m. next to Mono Way near Highway 108 in Sonora burned 2.9 acres and temporarily shut down Mono Way before it was contained at 3:30 p.m. Cause is under investigation.

+ A vegetation fire reported at 6:43 p.m. on Hogan Dam Road near Salt Springs burned a quarter-acre and was contained at 7:16 p.m. Cause is under investigation.

+ A vegetation fire was reported at 7:37 p.m. on Highway 12 near Burson and it burned one-tenth of an acre. Cause is under investigation.

+ A vegetation fire was reported at 7:47 p.m. at a homeless encampment on Stockton Road in Sonora burned .16 of an acre before it was declared contained at 8:10 p.m. Cause is under investigation.

+ A vegetation fire reported at 8:30 p.m. in the 4000 block of Rocky Road in the Mountain Ranch area burned a “small spot” before it was declared contained at 9:03 p.m. Cause is under investigation.

+ A vegetation fire reported at 8:58 p.m. in the Redhill Road and Running Springs Road area near South Ditch and east of Angels Camp burned a half-acre before it was contained at 9:20 p.m. Cause is under investigation.

+ A vegetation fire reported at 10:19 p.m. near Murphys Grade Road and Main Street in Angels Camp burned less than one-tenth of an acre before it was contained at 10:30 p.m. Cause is under investigation.

In the Stanislaus National Forest, where fire personnel recorded more than 70 lightning strikes earlier this week, a spokesperson put out information Friday morning about a lightning-strike fire reported at 1:44 p.m. Monday.

As of Friday morning it had burned one-tenth of an acre, said Diana Fredlund of Stanislaus National Forest public affairs. She said the fire was burning in a location called the Dome Inventoried Roadless Area, near Douglas Flat Day Use Area.

That’s about 25 miles east of Pinecrest near Highway 108 and west of Kennedy Meadows. There were 19 personnel assigned and one helicopter.

“The terrain is very steep and rugged, making firefighting access difficult and a safety concern,” fire crew supervisors said. “Firefighters are in strategic and safe locations near the fire to monitor fire behavior and to stop fire spread as needed.”

Cal Fire Tuolumne Calaveras Unit staff posted to Facebook at 8:25 a.m. Friday, “All too often during wetting rains in the summer we receive reports of fires only to determine these fires are actually someone burning debris piles.”

All burning is suspended, they said.

Anyone caught burning during a burn suspension is liable to civil and criminal punishments.

Contact Guy McCarthy at gmccarthy@uniondemocrat.com or (209) 588-4585. Follow him on Twitter @GuyMcCarthy.