Police are investigating the cause of an explosion and fire on the top floor of a three-story building at 15 Dolores Street, near Market Street.

TV news crews could be seen in the sky and smoke filled the air after the fire broke out at around 5:40 p.m. according to outlets like CBS SF.

The blaze was extinguished by 6:15 p.m once fire engines arrived at the scene.

Mission Local reports on the explosion that preceded and perhaps caused the fire, casting suspicion on a former, maybe lingering resident of the damaged third floor unit, an apartment from which locals believed he would sell drugs.

“[The explosion] rocked the building — I mean I felt it," said one tenant. "Then I walked outside to see what was up... All I saw was the smoke and fire."

At least nominally, the tenant added, the unit had been vacant since last week. “The people upstairs moved out just last Wednesday," he said, while noting there had been activity in the apartment since then — perhaps, he implied, from customers looking for drugs.

“The front door was locked but the back door was open,” he said, saying that the apartment may have been accessible via a back entrance and that it would be “easy to break into.”

The tenant and others knew the potential dealer as Ronnie. According to Mission Local, one resident said that, though Ronnie was supposed to be gone, "he could tell" that Ronnie had been there all week "because of his distinctive cologne."

Battalion Chief Victor Wyrsch said the third floor was subject to extensive fire damage, with some damage on the second floor. "We did an aggressive interior assault and put out the fire, everybody was out,” Wyrsch said. The unit was empty of nearly all furniture, and as is to be expected, the arson team is investigating. No injuries were reported.

The other previous residents at the burned unit were a woman in her 80s, and her two children in their 50s. Ronnie is described as being in his 30s. Another neighbor at 35 Dolores next door who seems to think he knows the score took and captioned the below video.

That's one way to get rid of the neighborhood crack dealer. Think our building will be ok.

A video posted by Joseph Killian (@jhkillian) on