Concerning twist in search for missing teenage girl Isla Bell after she disappeared from her Melbourne home almost three weeks ago

A desperate search for a missing teenager who disappeared 17 days ago has escalated and an investigation unit has been called in.

Isla Bell, 19, was last seen leaving her home in Brunswick, Melbourne’s north, around 6pm on October 4.

Her friends and family have since shared photos of the young woman online and urged anyone who sees her to contact police, especially if she is accompanied by an ‘older man’.

Ms Bell’s mother, Justine Spokes, shared her concerns online. “My girl is missing and dearly missed,” she wrote on Facebook.

‘She leaves an impression, she is difficult to forget. She has a fighting spirit, sometimes loud and sometimes soft, always persistent.

“We’re here for you, buddy. I love you, my carebear.”

Mrs Spokes later revealed the family had planned to visit the Great Barrier Reef for Mrs Bell’s 20th birthday and became alarmed when they could not reach her.

Isla Bell (pictured), 19, was last seen leaving her home in Brunswick, Melbourne’s north, around 6pm on October 4.

Mrs Bell (pictured) disappeared 17 days ago as friends and family asked the public to help find her

Mrs Bell (pictured) disappeared 17 days ago as friends and family asked the public to help find her

“Hey rascal. We look forward to our reef trip for your birthday coming up,” she wrote in a public message to Ms Bell.

‘We tried calling you to book flights. Let us know your opinion.

“We love you, my love.”

A close friend of Ms Bell, Tamara Griffiths, has also posted several updates on the search for the missing teenager.

She claimed the Fawkner Crime Investigation Unit has been assigned to the 19-year-old’s case.

“If you see anyone matching Isla’s description, especially in the company of an older man, please report it immediately,” Ms Griffiths wrote in a message.

‘Do not approach or intervene, your safety is also important.

“Isla is deeply loved by her family and friends. Every share, every pair of eyes looking out for her, brings us one step closer to bringing her home safely.”

Victoria Police are investigating Ms Bell’s disappearance and described her as having a “slender build, red hair, pale complexion and nose, lip and eyebrow piercings.”

“Police and family are concerned for her well-being due to the length of time she has been missing,” the statement said.

“Isla may have traveled to Melbourne’s CBD.”

Friends and family of Ms Bell (pictured) are urging anyone who sees her to contact police, especially if she is accompanied by an 'older man'

Friends and family of Ms Bell (pictured) are urging anyone who sees her to contact police, especially if she is accompanied by an ‘older man’

The Fawkner Crime Investigation Unit has reportedly been assigned to Ms Bell's case (pictured).

The Fawkner Crime Investigation Unit has reportedly been assigned to Ms Bell’s case (pictured).

Ms Griffiths shared a more detailed description of Ms Bell on Sunday, noting she is 160cm tall and weighs 55kg.

“Long waist-length red wavy hair, multiple facial piercings and tattoos on her right leg, left thumb – symbol, and left ring finger – love heart,” she said.

Anyone with information is urged to contact Brunswick Police Station on 8378 6000.