Police are growing increasingly worried about a 15-year-old girl from Bristol who has been missing for two weeks.
Madison, known as Maddie, disappeared on 26 April after leaving her foster parents' home in Southmead, saying she was going to the shops.
According to Avon and Somerset police, she has been known to use social media to meet people who might give her money and a place to stay.
She is described as white, 5ft tall and of average build, with brown shoulder-length hair.
Officers were going door to door in Southmead on Tuesday making inquiries and handing out leaflets with Maddie's picture on them.
Investigators have also released CCTV of the last known sighting of her.
The clip was filmed on 26 April on Santon Road at around 2.34pm and captures only her feet.
Detective Inspector Stuart Toms said that Maddie "is a vulnerable teenage girl who is at risk of being exploited and we urgently need the public's help to locate her and make sure she's OK.
"Maddie - if you see this please let someone know you're safe and well. Your family, foster parents and friends are worried about you.
"Maddie is very active on social media but she changes her accounts frequently.
"As well as appealing to anyone who might see Maddie to contact us, we're also keen to hear from anyone who sees her online to get in touch."
Anyone who sees Maddie is asked to call 999, quoting reference 5222098703.
Those who have information about her whereabouts or spots her online is asked to call 101, quoting the same reference number.