Sources close to the murder investigation told the Dhaka Tribune that "several contractors wanted to withdraw their money without completing the development work, but Delwar did not let that happen.
[11][12][13] However, in September 2019, Delwoar was made an Officer on Special Duty (OSD), which allegedly happened due to the lobbying of the corrupt and influential contractors, according to news sources.
On the same day, Turag police recovered his body at 3 pm, bearing head injuries, from Diabari Beribadh area[17] and sent it to Shaheed Suhrawardy Medical College Hospital in Dhaka's Sher-e-Bangla Nagar for autopsy.
[8][19] Turag Police recovered the mobile of Delwoar from the lake under Bridge no-3 of Diabari and the alleged microbus used in the killing from Gualanda in Faridpur.
[23] One investigation agency expressed to the Daily Deshrupantor that Delwoar was murdered because he didn't sign a construction bill equivalent of 12 million USD which was 3 times the actual cost.
[24] On 22 May 2020, the Institution of Engineers, Bangladesh (IEB) executive committee expressed their suspicion about other people’s involvement in the murder.
[25] Transparency International Bangladesh (TIB) demanded fair investigation into the murder and also asked the Anti-Corruption Commission to reveal the corrupt ring involved in the killing.
[8][9] Councilor M Selim Rahman and Mayor Jahangir Alam told a news media Channel i that the motive behind this murder could be the bribe money from City Corporation contractors.
[27] All officers and employees of Gopalganj LGED staged a demonstration on June 2, 2020 and demanded speedy trial and further investigation of the murder.
[28] Family members of Delwoar together with hundreds of engineers from Bangladesh and honourable teachers from BUET,[29] formed a human chain on July 18, 2020 and demanded arrest of masterminds behind the murder with an in-depth investigation.
[30] The family members claimed that anonymous people along with some officials of Gazipur City Corporation, asked them over the phone not to demand further investigation of the murder.