AUSTIN, Texas (AP) -- Authorities say investigators see "similarities" between the latest bomb to detonate in Texas' capital city and three bombs that went off earlier this month.

Police Chief Brian Manley said at a news conference Monday that although the bomb that injured two men who were riding or pushing bikes Sunday night seems linked to the three previous ones, the latest bomb involved a tripwire and those three were package bombs left on people's doorsteps.

Frederick Milanowski, the special agent in charge for the Bureau of Alcohol, Tobacco and Firearms, says the latest bomb is "more sophisticated" because it used a tripwire.

Manley says the two victims are men ages 22 and 23 and that they are hospitalized in stable condition with significant injuries.

Both men are white, as opposed to the victims of the three prior bombings, who were black or Hispanic. Those attacks killed two people and injured two others.

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