Divers found two more sharp spikes Thursday at Green Lake Park, bringing the total to 41 metal rods found this week at the south end of the lake.

Divers found two more sharp spikes Thursday at Green Lake Park, bringing the total to 41 metal rods found this week at the south end of the lake.

Seattle Harbor Police plan to conduct another sweep of the lake for extra measure, city parks officials say.

The spikes, roughly 2 or 3 feet long, were initially found Sunday night by a man wading near the boating center. They were buried at the bottom of the lake with the sharp ends pointed up.

The only injury reported was by Pat Boltz, the Seattle resident who suffered a foot injury Sunday when he stepped on a spike.

Parks officials believe the spikes may have been there as long as two months because some of the rods were corroded.

“It’s very strange,” said city parks spokeswoman Dewey Potter. “There couldn’t be any other reason [for the spikes] than to hurt people.”

Swimming at the boating center is prohibited, but parks staff have posted warnings to stay out of the water.

Sonia Krishnan: 206-515-5546 or skrishnan@seattletimes.com

Information from Seattle Times archives is included in this report.