Case study

An employee who started working for a security company after completing a short course and receiving the required permits. 
He passed an interview at "Shahaf" company, and they were impressed that he was suitable for the position.
He was asked to show a police clearance, and indeed he had no criminal record.
In addition, he was required to bring a medical certificate that includes psychiatric criteria.
He was hired on Thursday,
On Sunday he murdered his spouse, her ex spouse and her son.
If Background company had done a background check, he would not have been hired and would not have received a weapon.
Dov Tager, the employee who committed these murders, had many cases of domestic violence, past police cases and also many personality problems that would have been revealed in a comprehensive background check.

Remember: you never know who the person in front of you is.
The only way to find outIs to perform a background check and reveal the whole truth.