Every summer, Seoul turns a deep green, dense and lush under humid skies.
"Green leaves were falling to the ground, which shouldn't happen at that time of year," recalls Jung, who lives near the streetside ginkgo in Buam-dong, a residential neighbourhood in the north of Seoul.
The tree is beloved by locals, who believe it has occupied its spot for more than 100 years. With each passing day, her curiosity turned to concern.
The whodunnit engrossed Buam-dong and piqued the country's interest, making national headlines.
Their unlikely enemy was a museum built to honour a pioneering, nature-loving Korean artist.
Tucked between two mountains, Buam-dong is recommended by travellers and locals for its picturesque views, art galleries and cosy cafes - an escape from Seoul's bustle.
Because of its proximity to the Blue House, the president's official home, urban development has been restricted, allowing the neighbourhood to retain its quaint charm.
In a place where you usually find ginkgo trees in private gardens or untamed forests, this one is special, Jung says, because it flourished on the side of the road.
To Park Jeon-hee, who has lived here for nearly all his 74 years, the ginkgo is his "oldest friend".
The Whanki Museum had said that its outer brick wall was under strain from the tree's roots.
A local council representative told the BBC that an inspection last year found "no meaningful connection" between the ginkgo tree and damage to the museum wall.
Opened in 1992, the museum is dedicated to the late Kim Whanki, a painter and abstract artist, known by many as the "Picasso of Korea".