(Note at 7:50 a.m. ET, April 18: We've begun a new post to track Thursday's developments.)

Investigators made progress Wednesday, as they tried to determine who planted two bombs near the finish line of the Boston Marathon, leaving three people dead and injuring about 180.

The day after two bombs exploded near the finish line of the Boston Marathon, investigators began to unravel some of the details of what happened, and we began to learn about the lives of the three people who were killed.

FBI Special Agent in Charge Richard DesLauriers said that they believed the devices used in the attack may have been pressure-cooker bombs stuffed with BBs and nails. Investigators said the bombs may have been left inside nylon bags or backpacks.

Quoting "congressional and law enforcement sources," CNN is reporting that an envelope sent to a senator's office has tested positive for the poison ricin.

"After the envelope tested positive in a first routine test, it was retested two more times, each time coming up positive, the law enforcement source said," CNN reports. "The package was then sent to a Maryland lab for further testing."

Louisville Metro Police are urging people attending Saturday’s Thunder Over Louisville to report any suspicious activity to authorities.

The call comes after Monday’s explosion at the Boston Marathon left three people dead and more than 100 injured.

Jefferson County Public Schools has announced a partnership with Ford Motor Company Foundation to help the district improve its career-themed schools.

Louisville is one of 17 school districts nationwide participating in Ford’s Next Generation Learning initiative. The program includes a network of districts restructuring their career-themed schools to improve student outcomes and to prepare students for college and career readiness.

Indiana legislators have given final approval to a bill tightening the limits on how much consumers can buy of cold and allergy pills often used to make methamphetamine.

The state Senate voted 43-5 today in favor lowering the annual purchase limit of pseudoephedrine-based products to about 61 grams per person. That's about an eight-month supply of the current law's monthly limit.

The bill also increases the criminal penalties for anyone convicted of buying at least 10 grams of the medicines for a meth maker.

Kentucky Republican Congressman Thomas Massie has co-sponsored a bill that would allow individuals to ignore portions of the Affordable Care Act that violate their religious beliefs.

The Health Care Conscience Rights Act seeks to protect those who argue expanding coverage for contraceptives and abortion comes into conflict with their faith. For religious and political conservatives, the health care mandate to employers encroaches upon their constitutional rights.

According to Massie's office, the bill also protects health care providers who refuse to perform certain procedures and give refuge to people with religious convictions.

"Obamacare is expensive, unconstitutional, and threatens our First Amendment right of conscience," Massie said in a news release. "This bill protects churches, religious organizations, and business owners from being forced to violate their beliefs."

Expectations that Indiana will collect $290 million more in taxes leave Gov. Mike Pence’s team optimistic it can win a $500 million cut in the state's personal income tax this year.

House and Senate budget leaders said today that the improved fiscal picture makes it likely they will approve $500 million in tax cuts this year, but not necessarily the cut Pence wants.

State revenue forecasters said the improving economy should help Indiana bring in roughly $290 million more than the state previously anticipated.

The Courier-Journal has replaced its lone conservative columnist with three men, including a former White House staffer and former state House member.

Pam Platt, The C-J's editorial page editor, announced the changes this weekend in the paper.

The new columnists are: