How can a criminal search be conducted?

If you want to search criminal records online, there are many websites you can search the records. Sites like Intellus, Open Online etc help. Please refer the link in sources attached.

Another View: What records that are available on-line vary tremendously in quality and accuracy. The sites that compile this information gather it from the public records of whatever jurisdictions currently post them on-line. Be aware that MANY (probably the majority) of jurisdictions do NOT post this information on-line, mostly due to budget limitations and the labor cost of compiling and auditing the records.