Khan telephoned Rajapaksa and said that 113 people have been arrested so far, it said.
"All the videos and information related to the incident have been obtained by the Pakistani security forces," a statement from the President's office said.
Prime Minister Khan informed President Rajapaksa that Diyawadana, who had served in Pakistan for a long time, had shown a high level of professionalism as a manager.
In a shocking incident on Friday, angry supporters of the hardline Islamist party Tehreek-e-Labbaik Pakistan (TLP) attacked a garment factory and lynched its general manager Diyawadana, who was in his 40s, before setting his body on fire over allegations of blasphemy.
As pressure mounted on the Pakistani government to bring the guilty to justice, over 800 people have been booked under terrorism charges while 13 prime suspects are among 118 arrested so far in the horrific lynching of the Sri Lankan national in Punjab province.
Diyawadana, a graduate from the University of Peradeniya, is survived by his wife and two children. He left for Pakistan for employment in 2010 and has been working as the manager of the Sialkot factory since 2012.
He was working as the general manager in the Rajko industries (dealing in garments – sportswear) in Sialkot district, some 100 kilometres from Lahore.
Sri Lankan Parliament and Prime Minister Mahinda Rajapaksa on Saturday condemned the lynching and hoped that Prime Minister Khan will keep his commitment to bring all those involved to justice and ensure the safety of the rest of the island nation's expat workers.
"A mob of over 800 men gathered at the factory at 10 am Friday on reports that Kumara had torn a sticker/poster (inscribed with Islamic verses) and committed blasphemy. They looked out for him and found him (from the rooftop). They dragged him, beat him severely and by 11.28 am he was dead and the body was set on fire by the violent mob," Inspector General of Police (Punjab) Rao Sardar Ali Khan said.
The mob after burning the body of the Sri Lankan national had blocked the Wazirabad road. Police from different stations reached there to control the situation, he said.
The incident sparked widespread condemnation from all walks of life. Police were also chided for reaching the crime scene after the incident. Only a couple of policemen can be seen in one video asking the people to stay back while the body was burning.
Mob killings over allegations of blasphemy have been very common in Pakistan, where the crime can carry the death sentence.
In April 2017, an angry mob lynched university student Mashal Khan when he was accused of posting blasphemous content online.
A Christian couple was lynched and then set ablaze in a kiln in Punjab in 2014 after being accused of desecrating the Quran.