Police believe an overnight fire that extensively damaged an Orange hall was started deliberately.
The interior of the Salterstown Orange hall near Magherafelt was gutted in the blaze, with banners, collarettes and band instruments destroyed.
The Order Order said it was the 21st hall attacked in 2016 so far.
PSNI Detective Inspector Will Tate appealed for witnesses to come forward.
"Substantial damage has been caused to the Orange hall and we are treating this as deliberate," he said.
A spokesman for Salterstown Loyal Orange Lodge 482 said members were in a "state of shock".
"We are absolutely devastated that our property should be targeted in such a manner, and are simply crestfallen by the scene of devastation inflicted by the abhorrent individuals responsible," he said.
"The hall has been a part of community life for over 100 years, serving as a meeting place for local groups, and its unavailability for a period will be keenly felt.
"Despite this major setback, the lodge and the wider Orange fraternity will rally around and ensure our hall is once again fully restored."
Orange Order representatives are due to meet with senior police officers later this week to discuss the ongoing attacks on Orange halls.
"The Salterstown incident once again illustrates there remains a minority in Northern Ireland society who are prepared to use violence to attack the Orange Institution," said an Orange Order spokesman.
"They must not be allowed to succeed.
"We would also make an appeal for calm right across the community, and in particular that there should be no retaliation whatsoever for this attack. We, as an Institution, would not wish any community to suffer from such violence, having sustained so many attacks on our properties over the years."