Investigators announced that Armando Manuel Caballero, 27, a maintenance worker in the same building was found dead on Monday in an apparent suicide.
“Not including what’s happening today and right now, our emergency response team and others have conducted nearly 30 searches, since Miya has been missing, that spans three different counties and has included about 175 personnel,” said Sheriff John Mina.
He added that Caballero had worked at Arden Villas since June and had accessed Ms Marcano’s apartment with a master key.
The sheriff said they believed Caballero was responsible for Ms Marcano’s disappearance but admitted “we don’t know all the circumstances involved in what happened there”.
He would not give details about the specific role the FBI was playing in the investigation, but said the agency was assisting “in the manner of technology”.
Ms Marcano, known as “Mimi” to her father, had been living in and working for a student housing complex called Arden Villas in Orlando, close to the University of South Florida, though she was not herself a student there.
According to her Facebook page, she graduated last year from high school in Broward County, which includes the city of Fort Lauderdale.
Colleagues last saw her at the end of her shift around 5pm on Friday 24 September, though it wasn’t until Monday morning that Arden Villas posted a missing notice on its Facebook page.