The men, aged 38 and 39, were arrested after an acquaintance became suspicious and alerted the police.
During a raid on the home of the older brother, police found pictures and videos documenting the sexual assault of children. The 39-year-old had produced much of the material himself.
An investigation revealed that the 39-year-old had sexually assaulted a number of small children over a period of several years. In some cases the children were just a year old when molested by the man.
“He has admitted to assaulting certain children,” prosecutor Marie Louise Pettersson told the TT news agency.
The 39-year-old was remanded in custody in September before later being transferred to a psychiatric care facility.
The suspect’s younger brother has been charged with the alleged sexual assault of one child. The 38-year-old was held in custody for a few weeks during the winter before being set free again. He was rearrested in May and denies committing an offence.
The trial of the to brothers begins on Monday and is expected to run for seven days.