The body of Kylee McHugh, 46, was found inside her home by emergency services after crews responded to the fire in the Canberra suburb of Belconnen about 6.40am on May 18.
Detectives on Monday made a breakthrough in the case on Monday after the months-long investigation.
ACT Policing's Detective Acting Inspector Chris Watson told reporters a 27-year-old man had been arrested a day earlier.
He has since been charged with murder and arson.
"We believe that in the early hours of the 18th of May he did murder Kylee and subsequently set the house on fire," Act Det Insp Watson said.
"We conducted an extensive investigation and numerous forensic samples."
Act Det Insp Watson believes there are people in the community who know information about the crime.
He added the accused was known to Ms McHugh, with police describing it as an "association" rather than a "relationship of any kind".
"At this point in time (the 27-year-old) is the only suspect but we do believe there are other people that have more information and that can assist us.
"They may have information that isn't known to us and may be able to provide further insight into events that happened after her death."
Police did not provide information on how Ms McHugh died.
The accused man was known to frequent the area where Ms McHugh was killed, with detectives investigating whether drugs could have been involved.
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