A man has been arrested after a 16-year-old girl was stabbed to death on a rush-hour bus on one of Birmingham's busiest roads.
Christina Edkins was attacked on the bus on Hagley Road at about 07:40 GMT on her way to school.
West Midlands Police launched a city-wide manhunt to find her attacker.
The force said a 22-year-old man was arrested on suspicion of murder a "short while ago" near the Morrisons supermarket at Five Ways.
West Midlands Police said officers had spotted a man who was acting suspiciously who fitted the description of the suspect.
They said there had been a short chase on foot before the man was arrested.
Earlier Det Supt Richard Baker said every specialist officer in the city was involved in a "manhunt operation" for the suspect.
He said officers were pursuing the possibility that the attacker was known to the girl but said the murder investigation was still in its "very early stages" and said they did not want to speculate on the motive.
'Bright and popular'
Christina, who went to Leasowes High School in Halesowen, is understood to have boarded the bus minutes before the attack.
Head teacher Neil Shaw said Christina had been a "bright and popular student" who was "much loved by staff and students".
He added: "We are deeply saddened to hear this tragic news and our thoughts and hearts go out to her family and everyone who knew her.
"The school is working closely with the police and a team of counsellors to provide support to our pupils and staff."
The bus has been taken away from the scene, near the Five Ways junction of the Hagley Road, and the road has reopened.
'Distressed and distraught'
Mr Baker said the teenager's family were "distressed and distraught" at the news.
Officers said they were examining all CCTV in the area and police dogs and firearms officers were brought in to help search for the attacker.
A man who was earlier detained in the city centre by police has since been released.
Earlier, drivers reported traffic queues of about five miles backing up from Five Ways to where the Hagley Road meets the M5 at junction three.
A spokesman from National Express West Midlands said: "We can confirm that a tragic incident took place on a number 9 service this morning.
"Our thoughts and condolences are with the family of the person involved and we will offer all possible support to the police in their investigation into the matter."
Anyone with information can call police on 0800 096 0095.