Coral Jones and April’s stepgrandfather Dai Smith appeared with police at a lunchtime news conference in Aberystwyth today.
She said: “It’s been 36 hours since April was taken from us and there must be someone out there who knows where she is and can help the police find her we are desperate for any news.
“She is only five years old, please, please help us.”
Detective Superintendent Reg Bevan, from Dyfed Powys Police, earlier confirmed Mark Bridger's identity to end speculation – but stressed that Bridger was just one of several lines of inquiry.
Mr Bevan appealed for witnesses who may have seen Bridger, 46, between 5pm on Monday and yesterday afternoon, when he was arrested. They are also keen for anyone who may have seen Bridger's Land Rover Discovery 4x4 vehicle, registration number L503 MEP, to get in touch.
April was abducted from the Welsh town of Machynlleth at 7pm on Monday.
Mr Bevan said Bridger is currently being interviewed. He added: "We are in the process of piecing together his movements and that of the vehicle from around 5pm on Monday through to 3.30pm Tuesday.
"He was arrested on the A487 just north of the Dyfi Bridge, walking in the direction of Machynlleth, and he was wearing a camouflage green jacket, black waterproof over trousers and camouflage trousers beneath those.
"The Land Rover Discovery was recovered from a repair garage in the Old Station Road area of Machynlleth on Tuesday afternoon."
Mr Bevan said police are still pursuing a "number of lines of inquiry" – one of which is Bridger. He appealed for any information people may have about Bridger or his Land Rover, saying: "Did you see that vehicle between Monday evening and Tuesday afternoon?
"If you did please don't assume that someone else has already contacted us. Please, even if you have the smallest of information, it could be crucial to this investigation."
It was reported that Bridger is known to April's parents, Coral and Paul. They said they had been left "shattered" by her disappearance.
An overnight search involving 40 officers, dog handlers and mountain rescue teams failed to find the youngster.
Superintendent Ian John said they had been overwhelmed by support from the public, who have turned out in droves to help hunt for April.
But he warned of "challenging conditions" facing search and rescue teams and asked people to leave today's efforts to "members of our trained and skilled teams".
Mr John said police and a mountain rescue team carried out "systematic and methodical" searches around Machynlleth throughout the night.Today's efforts were to concentrate on potentially dangerous areas of deep woodland and the River Dyfi around the town.
Mr John said: "The River Dyfi is in flood and we really do need to manage the risk of everybody there, not only the police officers, the mountain rescue team, but we are extremely concerned about large numbers of members of the public going into what I have said are very challenging conditions.
"So what I am asking really is, notwithstanding the great support and the commitment that people want to show in helping us to find April, can we please leave this now to the trained and skilled people that we have?
"I don't want those officers to be distracted by the well- intentioned and enthusiastic support."