A woman was sexually assaulted in her own home in Harrow, prompting a police investigation.
Detectives from the Metropolitan Police Sexual Offences Exploitation and Child Abuse Command are appealing for witnesses and information following the incident on January 19.
A woman returned to her home, in Cambridge Road, at around 7.20pm, to find it had been broken into via a rear patio door. She was confronted by a burglar inside and was seriously sexually assaulted.
Officers believe there may have been up to three men involved in the burglary. They left the property in a white Nissan Qashqai which was later found in Southfield Park. It is possible that another vehicle was parked nearby.
A laptop and jewellery were stolen in the burglary.
The man who allegedly sexually assaulted the victim is described as a light-skinned black or mixed race man, between 25 and 30-years-old, 6ft tall, with short dark hair. He was wearing dark clothing and gloves.
Another burglary occurred earlier in the evening, at 5.45pm, nearby in Marsh Road, in which jewellery was stolen.
Police said it may be connected to the other incident.
Three men ran off when disturbed and used a car to escape the scene, possibly a Volvo S60 or S80.
Detective Chief Inspector Adam Lowe said: "This is an abhorrent crime suffered by a female in her own home.
"I remain open-minded as to whether the two burglaries are connected but I can reassure the community that my team are committed to bringing those responsible to justice and I appeal to anyone with information to contact us."
Cambridge Road is a well used commuter cut through from North Harrow Tube Station. Officers are particularly interested in speaking to anyone who was in the area on this day and may have witnessed the burglars in the area or seen anything unusual.
Police would like to speak to anyone who say anything suspicious in the Marsh Road area around 5.45pm, in Cambridge Road between 7.15pm and 7.30pm, or anyone who saw the white Nissan Qashqai in the area.
Anyone with information should call 020 8217 6541 or Crimestoppers anonymously on 0800 555 111.