He started as a "shooter", when he was 18 years old.
His primary task was to kill those who refused to pay money to top-listed criminal Shahadat Hossain. For each "killing mission", shooter Rafiqul Islam Rony used to charge around Tk 5 lakh.
Whenever any such order came from Shahadat, who is believed to be hiding in India, Rony carried out the order without asking question. For each "mission", he never took more than three associates with him.
An accused of at least eight cases with different police stations in the capital's Mirpur, Rony is also a life-term awarded convict in a murder case.
Police's Detective Branch (DB) disclosed the findings after arresting Rony and four others from the capital's Bhasantek area on Thursday.
The other arrestees are Monir Hossain Babu Alias Desperate Babu (34), Saiful Islam (35), Saheen Miah (39) and Sohel Rana (31).
Police also seized a foreign-made pistol and four machetes from them.
The arrestees were produced before a Dhaka court, which put them on two-day remand each for interrogation, Shahadat Hossain Sumon, additional deputy commissioner of DB (Tejgaon division) police, told The Daily Star yesterday.
Yesterday was first day of the remand.
On December 12 of 2013, Rony and his friend Mohosin alias Killer Mohosin demanded Tk 50 lakh from a businessman of Mirpur 10 area for construction of a residential building.
As he refused to pay the money, Rony and Mohosin allegedly killed the businessman's son, said Md Rajon, complainant of the case and also a brother of the victim.
The court later gave them life-term imprisonment but they had never been arrested, said police.
On July 31, Mohosin was killed in a "shootout" with Rab. After that, Rony went into hiding, said ADC Sumon.
"Arrestee Saiful and Sohel are close associates of Rony. They used to collect extortion money from different areas of Mirpur in name of top-criminal Shahadat and send it to him in India every month," he said.
Another arrestee Babu mostly worked for top-criminal Jamil and his brother Mamun. Babu also used to send money to Jamil in India and Mamun in Nepal, said ADC Sumon.
Babu is wanted in a number of cases filed with Pallabi and Bhasantek police stations.
The activities of criminals Jamil, Mamun and Shahadat came to the fore following arrest of three associates of Jamil on July 29 on charges of killing two ruling party leaders in Mirpur.
Police sources said these criminal gangs, especially Jamil, took contracts to kill either Pallabi Jubo League general secretary Juwel Rana or councillor of ward-6 Taizul Islam Bappi.
The criminals were given the contracts for Tk 5 crore to take control over "extortion scene" in Mirpur and Pallabi areas, according to sources.
But the "dramatic bomb explosion" inside Pallabi Police Station foiled their plan, according to police officials involved with the investigation.
Asked about it, ADC Sumon said they have learned about the plot but did not find involvement of these five arrestees.
"The associates of these top-criminals went into hiding after the arrest of the five. We, however, got their identities and some locations and we are now conducting drives to arrest them," he added.