AUSTIN (AP) — Austin police say the reward for information leading to the arrest of whoever is responsible for three explosions that have killed two people and injured two others has risen by $50,000 to now total $115,000.

Interim Police Chief Bryan Manley announced the reward boost Sunday as authorities pleaded for help.

Officials believe the bombings this month are related but Manley says investigators don’t have a motive or “what the ideology is behind this.”

He says more than 500 officers, including federal agents, have conducted 236 interviews in following up 435 leads.

A package bomb exploded at an east Austin home on March 2, killing a 39-year-old man. Two package bombs in other parts of the city exploded last Monday, killing a 17-year-old, wounding his mother and injuring a 75-year-old woman.

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