Not sure if this will help or not. But I did a search on FDNY's official government website, and I found this. I have a feeling there may have been a typo on the last name. Not sure though. Hope it helps.
WILLIAM DELVIN BATT. CHIEF, BAT. 4 Injured SEP. 20, 1911 Sep 24, 1911 516 BROOME ST. FELL FROM ROOF
On Saturday, October 2, 2004, at 1130 hours, a Park Dedication will be held honoring the memory of Battalion Chief Dennis L. Devlin, B-9, who made the supreme sacrifice on September 11, 2001. The dedication will take place at Olmstead Avenue and Ellis Avenue, Bronx, near the quarters of E-64/L-47. The Park will be named in his honor. All off-duty members and their families are invited to attend as a mark of respect to the deceased. Members are requested to attend in dress uniform.