Offer Letter And Payslips Are Verified Or Not

I come accross a case where one of my friend altered the offer letter and payslips.He submitted that to a new organization and they accepted that too.Best part is his new package was given on the basis those altered Salary Slip and Offer Letter.Is that possible how can such loop hole exist.
Won't the new employer verified that Payslip and Offer Letter ?

Before reply to your query would like to know your role in this. Secondly it is the purview of the employer to check the Background Verification or not. Last but not the least employees are selected on the basis of their skills and paid accordingly.

I am that person colleague and come to know about this from him.Here i am keen to know is that how fake salary slips and offer letter verified by the employer.Means one can show up any thing ?

Dear Friend
With a view to get a job by submitting fake salary / experience certificates is not ethical on part of any one. The employer is expected to assess the genuineness of certificates produced by each candidate at the time of interview itself. On his failure to do so, we need not blame your friend for his submission of fake certificates. Generally, in interview, employer will prefer to see the capability of candidate for required position and ones he satisfied with this basic aspect, some employers may not prefer to check other aspects of verifying certificates etc
Regards