@ CIA can verify if your car has been involved in any criminal act. The office is on Abbott road near opposite PTV station.
@ Freed Court House, Exise and Taxation Office you can verify the ownership information and if any duplicate registration of the car been issued and if issued, why it was issued etc.
@ local post offices, you can verify for the car's last paid token and if that token is original or fake.
I have had this experience while selling my Khyber that was with Duplicate registration book. The buyer wanted to verify everything by himself and not involving any dealer/agent so that no hanky panky could be overseen.
When i purchased this particular car, i opted to get the transfers done through the car dealer that i purchased the car from to avoid the hassle but this was a bad decision, the dealer could have easily made fake receipts and would not even know until checked through above authorities myself.
I recommend if anyone wants to buy a used car, atleast to go through these three processes themselves and to avoid involving agents.