Nazimuddin Samad, a masters student of the state-run Jagannath University's law department, was killed by suspected Islamist militants in Old Dhaka's Sutrapur area on Wednesday night.
The hacking took place on the night of February 4.
Immigration officials confirmed that Arshad, who was the second secretary at the political section of the high commission, left Dhaka on a Pakistan International Airlines flight on Wednesday afternoon.
A Hindu religious congregation at a International Society for Krishna Consciousness temple in Bangladesh was attacked by unidentified gunmen who hurled bombs and fired gunshots at the worshippers, injuring two people in the second such incident in the same area in less than a week.
Over 5,000 people were witnessing an open-air show organised to mark the Rash Mela festival when three crude bombs exploded on the premises of Kantaji Temple in northwestern Dinajpur.
Bangladesh Supreme Court on Wednesday upheld the death sentences handed down to two top opposition leaders convicted for war crimes committed during 1971 independence war against Pakistan, rejecting their final review petitions.
A Bangladeshi publisher, who worked with slain atheist writer and blogger Avijit Roy, was on Saturday hacked to death by unidentified assailants in Dhaka, shortly after two secular bloggers and another publisher of Roy were attacked in a separate incident.
Cesare Tavella, 50, was shot thrice from a close proximity on Monday evening in Dhaka's Gulshan diplomatic zone while he was jogging, police said.
The 40-year-old blogger was attacked by four suspected Al Qaeda linked Islamists at their apartment
Nur Mia was arrested, becoming the eighth person to be held over the July 8 killing of the boy.
The video of the torture, which was posted on Facebook, triggered outrage, forcing authorities to launch a manhunt.
50 others were injured in the stampede that took place when hundreds of people stormed the home of a businessman in northern Bangladesh for a charity handout during the holy month of Ramzan.
The authorities have launched a search operation to trace the missing pilot identified as Flight Lieutenant Tahmid.
35 others have been injured in the landslides and flashfloods triggered by torrential rains.
Bangladesh, which shares border with five Indian states, has strategic importance for India and Prime Minister Narendra Modi's visit.
Bangladesh on Monday banned an Islamist militant outfit that is believed to be behind the gruesome hacking deaths of three secular bloggers.
A secular blogger in Bangladesh has been hacked to death in north-eastern Bangladesh in the third such deadly attack since the start of the year, police say.
A court in Dhaka on Wednesday ordered the arrest of former Bangladesh prime minister Khaleda Zia, scrapping her existing bail in connection with two graft cases after she did not appear for the hearing citing "security reasons".
At least 48 people, including many women and children, were killed on Sunday when an overcrowded ferry with over 150 passengers sank after a collision with a trawler
A Bangladeshi oil tanker carrying over 3,50,000 litres of furnace oil sank on Tuesday in a river in the Sundarbans leaving its captain missing while leaking its cargo and endangering the world's largest mangrove forest.