Two men have been arrested separately in connection with the suspected murder of missing teenager Alice Gross.
Officers have stressed the disappearance of the 14-year-old schoolgirl, who was last seen on August 28, remains a missing persons inquiry.
But a search area has been expanded as specialist police divers continue examining the Grand Union Canal near her home in Hanwell, west London, where she was last seen.
On Sunday, a 51-year-old man was arrested in Hanwell on suspicion of Alice's murder.
That followed the arrest of a 25-year-old man from Ealing on Saturday for the same offence. Officers have said the two men are independent of each other.
Both men remain in custody at a west London police station, after police were given more time to question the 25-year-old.
Alice, who suffers from anorexia, went missing 12 days ago after failing to return home.
She was last seen by her family at 1pm on August 28, and was spotted on CCTV at 4.23pm on the same day walking along the Grand Union Canal.
Officers have released new pictures of five cyclists seen riding along the canal at the same time Alice went missing.
The images show three cyclists passing the Trumpers Way Canal Bridge in Hanwell, just before Alice walked past.
They are followed by two more cyclists who pass under the bridge.
Alice is white, 5ft 2ins tall, of very slim build and with shoulder length, light brown hair.
She was last seen wearing dark blue jeans and a dark green lacy cardigan and carrying a dark rucksack. The bag was recovered last week.
She could have been wearing denim blue Vans shoes and tartan-framed glasses.
Officers have urged anyone who befriended Alice at a song-writing workshop at the Camden Roundhouse to contact police.
Last week, Alice's mother Rosalind Hodgkiss said: "We'd like to say to Alice first of all that we miss her, that we love her and that she's not in any trouble, and we want to know that she's safe. We just want her to come home.
"We're also appealing to anybody who might have seen her or who may have made contact with her or who may know something about her whereabouts to contact police or Missing People, and to just get in touch because we're really concerned about her well-being."
Anyone with information can call police on 020 8358 0100, Ealing Missing Persons Unit on 020 8246 1018 or the charity Missing People on 116000.