An animal-rights activist suspected in bombings at two locations in Northern California over two decades ago — and who landed on the F.B.I.’s list of most-wanted terrorists — was caught in Wales on Monday, the F.B.I. said on Tuesday.

The activist, Daniel Andreas San Diego, 46, was sought in connection with the bombings of two San Francisco-area buildings that housed companies with ties to animal testing.

Mr. San Diego was accused of planting two bombs at Chiron Corporation, a biotechnology company in Emeryville, Calif., on Aug. 28, 2003, and another on Sept. 26 that same year at Shaklee Corporation, which makes health, beauty and household products in Pleasanton, Calif.

The F.B.I. said that Mr. San Diego targeted those corporations because they had worked with a company that had conducted experiments on animals.

No one was injured in the attacks, but the F.B.I. said that the construction, placement and timing of the devices made it clear that Mr. San Diego intended to cause serious harm. The bombings caused minor property damage.

At Chiron, the first bomb detonated early in the morning, the F.B.I. said, and the second bomb was set to detonate an hour after the initial blast, which the agency said was likely intended to kill or injure emergency medical workers. The second device was found before it was to go off and the area was cleared.

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