The personal security officer of sacked Uttrakhand Minorities Commission Chairperson Sukhdev Singh Namdhari was arrested on Monday in connection with the Ponty Chadha case even as police said they were probing whether the former fired at the liquor baron.
With this, the number of people arrested in the shootout in which Ponty and his brother Hardeep Chadha were killed rose to nine.
Namdhari, an aide of Ponty, was arrested on charges of murder while seven others were arrested on charges of trespass, kidnapping and dacoity.
Tyagi (27) is charged with criminal conspiracy and other related sections.
"We have arrested Sachin Tyagi, a gunman Constable of Uttrakhand Police for his role in conspiracy that led to the murder of Hardeep Chadha," S B S Tyagi, Deputy Commissioner of Police (Crime), said.
During investigations, he said, it emerged that Tyagi had unauthorisedly arrived in Delhi along with Namdhari and used his official weapon unauthorisedly and fired towards Hardeep.
Namdhari himself was in possession of 0.30 bore pistol but did not possess valid licence for bringing the weapon to Delhi, he said.
Tyagi joined as a constable in Uttrakhand Police in 2005 and was attached with Naamdhari as his PSO since January 2012.
Delhi Police had alleged Namdhari had also opened fire at Ponty's brother Hardeep during the shootout at Chattarpur on November 17 in which both the brothers were killed. Namdhari had said he did not fire at Hardeep.
A senior police official said they were investigating all angles including whether Namdhari fired at Hardeep resulting in his death. "We are not leaving any angle," the official said.
Asked about Tyagi's role, he said the PSO allegedly made false statements before investigators and helped in destroying evidence.
The official claimed that Namdhari allegedly handed over to Tyagi the gun he used to open fire at Hardeep.
"Tyagi handed over the firearm to one Sonu who in turn gave it to Satnam. Tyagi knew this was an important evidence but he helped Namdhari," the official said.