The first suspect was detained last week and held for questioning about the fatal stabbing of Lindh in a Stockholm department store Sept. 10.
The arrest of the second suspect was announced as police confirmed the freeing of the first man, the BBC reported Wednesday.
They said he had been arrested "without incident" but did not reveal his name or the circumstances of his detention.
The first suspect, named in newspapers as Per Olof Svensson, 35, was detained on Sept. 16.
Police had been hunting for a man filmed by closed-circuit cameras in the department store shortly before Lindh's murder.
Last Friday, a Swedish court gave police permission to hold the first suspect for a further week, after prosecutors said there were reasonable grounds to suspect the man.