Officers carried out new raids overnight to root out a possible support network for the men, accused of ploughing vehicles into pedestrians on Barcelona's busy Las Ramblas boulevard and a seaside promenade in the resort town of Cambrils, claiming 15 lives including a young boy and wounding more than 120 people.
The international connections of the cell of mostly Moroccan nationals have also come under scrutiny, with talks later today between Spain and France's interior ministers expected to focus on the case.
At least 500 litres of acetone, large quantities of nails and detonators as well as gas canisters have been found at a house in the town of Alcanar, court documents said.
They are ingredients of TATP - the explosive of choice of the Islamic State group, which has claimed its "soldiers" carried out the attacks.
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But an accidental blast at the bomb factory in Alcanar on August 16, the eve of the Barcelona van attack, forced the cell to alter its plans and turn to vehicles as killing machines.
They rented a van the next day, but again suffered a false start as it was involved in an accident not far from Cambrils.
A second van was used two hours later in the Barcelona rampage.
The suspects then bought four knives and an axe that were used to slash at pedestrians in Cambrils in the early hours of Friday.
After a full day court hearing, Chemlal and another suspect, Driss Oukabir, 28, were remanded in custody and charged with terror-related offences.
The judge gave himself three more days to decide if the fourth suspect, Salh El Karib should be remanded or released. His shop, which allows people to make calls abroad, was among targets of police raids late Tuesday.
An apartment in the village of Vilafranca del Penedes, 50 kilometres (30 miles) west of Barcelona, was also searched, a police spokesman told AFP.
The men in court yesterday were the only surviving suspected members of the terror cell, which Spanish police claimed they had dismantled after gunning down the last man at large, Younes Abouyaaqoub, on Monday.