Suspension from work

Hi, ask ko lang po regarding sa case nung cousin ko, she is currently suspended from work for 30 days (together with 3 of her workmates) CASE: Sales money was lost from the store. They are working in a clothing store in a mall in Q.C. Their sales for the previous day which was kept in a cashier's box inside was lost and when they got there the following day. There was no force entry to the store, and when the Mall admin reviewed the CCTV they saw a person went back that night and re-opened the store. Two of the suspended employees being the key holders was a suspect of either the crime itself or as an accomplice to the crime. Two others were the ones who were on duty that day.

While they are still doing investigation all four are now suspended, salaries on hold including 13th month pay.

Question: Is is lawful for the company to do that? Aren't they (suspended employees) are entitled to their salaries and 13th month pay? Is the suspension & salary hold-out fair & lawful?

What do they need to do? What are their rights??? Can they at least demand for their salaries???

Your respond and help will be highly appreciated.

Thanks so much!

Addt'l. info: There's this one guy employee (key holder) who just AWOL himself a day before that crime happened. He gave back the keys mid afternoon of the next day after he decided not to report to work anymore. For your info.