The killing near the capital's diplomatic zone was the first in a wave of attacks to be claimed by the Islamic State group, and was followed days later by the gunning down of a Japanese farmer in northern Bangladesh.
   
Bangladesh authorities rejected the IS claim of responsibility, saying the group had no presence in the country.
   
The government and police say homegrown militants are responsible for the deaths of nearly 50 secular activists, foreigners and religious minorities killed over the last three years.
   
They say the deaths are part of a plot to destabilize the country, and have blamed the main opposition Bangladesh Nationalist Party (BNP) and its Islamist ally.
   
Deputy commissioner of Dhaka Metropolitan Police Sheikh Nazmul Alam said seven people had been charged with the murder of 50-year-old Italian Cesare Tavella, including two BNP officials.
   
“We submitted the chargesheet against the seven on Monday. Those who are charged include Abdul Quayum who masterminded the attack,” Alam told AFP, referring to a senior BNP official who is believed to be living in exile in Malaysia.
   
He said the attack was part of a plot “to tarnish the image of the country and destabilize it”.
   
Quayum denied the charge, telling the Daily Star newspaper he was being victimized because of his political affiliation.
   
BNP spokesman Ruhul Kabir Rizvi said the charge was “false and politically motivated”.
   
“It is an attempt to hide the real killers,” Rizvi told AFP.
   
Bangladesh this month launched a nationwide crackdown on local jihadist groups, arresting more than 11,000 people, under pressure to act on the spate of killings.
   
But many rights groups allege the arrests were arbitrary or were a way to silence political opponents of the government.
   
Experts say a government crackdown on opponents, including a ban on the country's largest Islamist party following a protracted political crisis, has pushed many towards extremism.
   
Dhaka police chief Asaduzzaman Khan said after Tavella's death that his murder was intended to “embarrass the government” and prove the country was unsafe for foreigners.
   
International schools closed temporarily after the murders and embassies restricted their diplomats' movements, while Australia's cricket team cancelled a planned tour over security concerns.