Nearly 400 families were forcibly evicted from the Borei Keila site this month.
Provincial Police Chief Chhoung Seanghak said police are working the case and focusing on the two guards.
The Documentation Center has collected nearly 1 million documents on the Khmer Rouge since 1995.
Cambodia is pushing for a seat on the council, UN Security Council, for 2013 and 2014; voting will be held later this year.
HRW also detailed what it views as severe violations of human rights in nations including Cambodia, Indonesia, Malaysia and Vietnam.
Phan Imex was supposed to build 10 buildings to house evicted residents and built eight instead.
Witnesses said security guards for the TTY Company opened fire with AK-47s.
Escapees climbed over the walls or jumped the metal gates of the Prey Speu Social Affairs Center Wednesday in full view of observers.
In her letter to the court, shared with reporters, she said she had paid the fine in full, from reductions in her parliamentary salary.
Thirty-eight people remain in unlawful detention after they were seized by authorities as they protested outside City Hall this week.
The demonstrators were seized Wednesday, where they had demanded the courts release eight representatives arrested earlier this month.
Around 300 families lost their homes in the Jan. 3 forced eviction of Borei Keila.