They arrested a suspect, named Raja Gaman, who confessed to the crime. He revealed that he has been smuggling drugs and weapons from Balochistan to Punjab in ambulances for almost four years now.
As of the filing of this report, police said that further investigation is underway.
Source: https://www.pakistantoday.com.pk/2019/03/27/10kg-hash-recovered-from-ambulance-in-dg-khan/