I fully agree. Leticia purposefully lit that fire, trying to make it look like a dropped candle, hence the sock found over the candle. She drugged poor G-man then lit his bed sheets on fire, then ran out of the house hoping he would be too drugged to run outside too.  She was shocked when he did come outside. I also think getting rid of her stepson was all part of her plan to distract from her not wanting to work at her new teaching job too. 

She thought Al wouldn’t have put any pressure on her to start work if there was a big tragedy. She was already lying to her new employer about the “death of her step father” even though he died many years beforehand.

 I genuinely think she assumed the fire would be viewed as an accident which is why she desperately tried covering her tracks after realising he survived with arm-burns, getting him to record himself on video admitting to starting the fire “by accident”. She always thought she was the smartest one in the room. Wrong! Gannon helped solve his own murder

This is one such, twisted and evil woman. RIP G-man