In an email to employees on Wednesday, Airbnb CEO Brian Chesky said the company is taking “significant steps in designing” trust into the service by implementing changes that include full refunds for guests unsatisfied by their Airbnb’s upon check-in, reviewing all listings for quality and accuracy, and a hotline that anyone can call at any time to report an issue. 

The updates follow a shooting that killed five people at a Halloween party at an Airbnb in Orinda, California and a Vice report about Airbnb scammers that take guests money only to provide them with an often run-down place to stay. The FBI is reportedly looking into the issue.   

In his email, Chesky said that Airbnb’s service is driven by trust, which has helped the company grow to serve more than 600 million people.

“Recently, events by bad actors on our platform took advantage of that trust, including at a home in Orinda, California,” Chesky wrote in the email. “We intend to do everything possible to learn from these incidents when they occur.”

The latest safety and integrity concerns about Airbnb’s business could potentially delay what is expected to be a blockbuster initial public offering by Airbnb next year. The company, valued at $31 billion following its latest round of funding in September 2017, is not expected to be among some of the latest big money-losing companies that debuted on the public market this year.

Chesky, in his email, outlined four solutions aimed at addressing the latest issues. 

Starting Wednesday, Airbnb plans to review the 7 million listings on its service, making sure each is accurately represented and meet all standards including cleanliness, safety, and amenities. Chesky said by Dec. 15, 2020, the company expects to have all homes listed on its service verified.

The company also is promising to do more if guests aren’t satisfied upon arriving at their booked Airbnb. The company said if the booking does not meet Airbnb’s standards, guests will rebooked at a new listing of equal or greater value or will receive a full refund. The company reportedly previously offered some guests only partial refunds if they weren’t satisfied.

To address safety concerns, Airbnb is creating what it’s calling a neighbor hotline, which will allow anyone to reach a company representative at any time of the day. The hotline, expected to debut in the U.S. by Dec. 31 and globally over the next year, will be manned by a rapid response team. Airbnb has enlisted Charles Ramsey, former chief of police in Philadelphia and Washington, D.C., and Ronald Davis, former chief of East Palo Alto Police Department, as advisors.

Lastly, Airbnb said it will expand its manual screening of reservations its systems flag as “high-risk” starting Dec. 15. The company looks at factors including length of stay and size of the listing among “hundreds” of other data points to determine which reservations might be suspicious.

More must-read stories from Fortune:

—Uber Eats’ hungry new strategy: dominate or exit
—The mobile price wars are on. Here’s how much you can save
—What works and about Apple’s new Beats Solo Pro headphones
—China’s 5G is ahead of schedule, on a spectrum the U.S. can’t match
—New bank offers 3% interest rate for ‘good behavior’
Catch up with Data Sheet, Fortune’s daily digest on the business of tech.