He comes across as someone speaking about a case that he's not very familiar with...
And, frankly, we have a long history of high level government executives who were not tool sharp.
Hosko was an FBI agent since 1984 who retired after 30 years of service. He spent the latter part of his career in Washington DC so JMO but he probably has many many contacts in local law enforcement that is investigating this crime
As for being not "tool" sharp...? He seems pretty accomplished to me
FBI.gov:
In 1992, Mr. Hosko began serving on the Chicago Violent Crimes Task Force, where he focused on violent crime and fugitive investigations until he was promoted to supervisor in 1995. In this role, he continued to serve on the task force while also leading investigations into various federal crimes.
In 2001, Mr. Hosko reported to the Critical Incident and Response Group, first as supervisor and then as unit chief of the Crisis Management Unit. In this role, he served as deputy to the Joint Operations Center commander during the Winter Olympics in Salt Lake City, Utah, and led the FBI in its interagency cooperation during the 2002 sniper shootings in Washington, D.C.
In 2003, Mr. Hosko was promoted to assistant special agent in charge of the Philadelphia Division, where he was responsible for investigations into criminal matters. While in this role, he led the division’s surveillance and technical operations, and he served as the program supervisor for crisis management. In 2005, Mr. Hosko served as the on-scene commander of FBI personnel deployed to Afghanistan in support of Operation Enduring Freedom. Later that year, he served as deputy to the senior fellow law enforcement official following Hurricane Katrina.
In February 2006, Mr. Hosko served as deputy on-scene commander for FBI personnel supporting the Winter Olympics in Turin, Italy. He was promoted to inspector in 2007, before being assigned to his most recent post with the Washington Field Office in 2010.
He is FBI with 30 years experience investigating violent crimes. He is familiar with evidence collection and investigative procedures.
The fact no other arrests have been made IMO, indicates Hosko might be correct that no evidence implicating others has been discovered and Wint indeed acted alone.